Is This a Kissing Blog?

wide the-princess-bride-kiss

Buttercup and Westley’s final kiss in Rob Reiner’s 1987 adaptation of William Goldman’s classic, The Princess Bride

“Since the invention of the kiss, there have only been five kisses that were rated the most passionate, the most pure. This one left them all behind.” –The Princess Bride

Ah, wuv. Twue wuv. With that record-shattering kiss, Buttercup and Westley traded vows of everlasting love, the promise of a lifetime’s “As you wish”es, and approximately 80 million bacteria.


Yes, a research group at TMO in the Netherlands investigated how kissing affects a couple’s oral bacteria and found that Valentines swap more than just spit. Just like in your intestines, stomach and skin, your mouth and airways are home to a whole host of bacteria that help keep you healthy, known as your microflora.

Oral bacteria were almost certainly the first to be viewed by humans when back in 1683, Antonie van Leeuwenhoek (the father of microbiology) scraped some tarter off his own teeth and stuck it under a microscope. As many as 600 different species of bacteria can be found in the human mouth, some of which are responsible for common problems like gum disease and tooth decay. However, keeping the bacteria living in your mouth happy and balanced helps keep out disease-causing bacteria, stops bad breath, and may even help prevent more serious diseases elsewhere in your body, including stroke, cardiovascular disease, and diabetes.

While the makeup of a person’s microflora is important, it isn’t static. The mouth is an open system, meaning that the composition of the bacteria living there can be changed by things like your genes, age, diet and who you…interact with.

princess bride grandson

INTIMATE kissing? Are you trying to kill me?


The Dutch research group that performed this study swabbed the mouths of random visitors at the Artis Royal Zoo in Amsterdam. Then, the researchers had them make out for ten seconds before re-sampling. You can’t make this stuff up.

The researchers found that among their amorous zoo-goers, romantic partners had more similar oral microflora composition pre-kiss than two people not in a relationship. In particular, partners showed the most striking similarities in the microflora associated with their tongue. The long-term couples’ microflora didn’t change much post-kiss, but this is most likely because they are in like with each other and already swap bacteria fairly regularly.


The scientists conducting the study then wanted to know precisely how many bacteria are passed around per make-out sesh. To answer that question, they gave one partner of each couple probiotic yogurt containing what they referred to as “marker bacteria” and, again, had them snog away.

They then resampled everyone’s mouths to see how much bacteria had transferred from the person who ate the yogurt to the person who did not. It turns out that on average, 80 million bacteria were swapped from one mouth to the other per 10-second make-out.

aaaaaas youuuuu wiiiiiiiiiish

Aaaaaaaaassss youuuuuuuuu wiiiiiiiiiish!


True love is not as easy as one simple kiss, however; it requires effort and real commitment. In fact, the researchers found that in order for a couples’ microfloras to really change to resemble each other, they need to kiss — intimate kissing, they specified — nine times per day.

So, friends, to have the sort of love that cannot be tracked, even with a thousand bloodhounds, that cannot be broken, even with a thousand swords, that is second only to a good MLT — remember to say those three little words every time your Valentine wants a smooch: As you wish.

Life on Mars

M. Dudouyt’s creepy Martians from the 1917 edition of H.G. Wells’ classic novel, The War of the Worlds

The idea that extraterrestrial life may be out there is one that has captured our species’ collective imagination for centuries. It’s possible that being able to share this incomprehensibly vast universe with someone else makes us feel a little less alone. It’s equally possible that we just want advanced alien technology without the effort and expense associated with inventing it ourselves. Perhaps that’s why the theories suggesting that there is, or ever was, bacterial life on Mars is such an attractive one to Terrestrial scientists.

The presence of even unintelligent life on a planet as nearby as Mars would mean that, however improbable it may be, life somehow found a way to exist twice in the same tiny corner of the galaxy. If that’s the case, what’s to say it’s as rare as we think it is? If life could be found just next-door, we reason, the void stretching between us and another intelligent species might not be as expansive as we previously thought.

Speculation that life could be found on the Red Planet is not a new one – from Edgar Rice Burrough’s John Carter of Barsoom to the Looney Tunes’ Marvin the Martian, little green men (or huge green men, as the case may be) have played a prevalent role in science fiction since its inception. However, it wasn’t until the mid-1990s that fantasies about Martian life began to bleed into the realm of possibility.


On December 27th, 1984, the scientific community received the best Christmas present it had been given in a long time when a National Science Foundation team found a meteorite in the Allan Hills of Antarctica. The meteorite, now named ALH84001, was described by the team as being grayish-green, highly-shocked, and the rarest find of that season. Additional remarks in the field notes include simply, “Yowza-yowza.”

Nine years of analysis revealed that the meteorite was both of Martian origin and incredibly ancient; radiometric dating determined that ALH84001 is approximately 4.1 billion years old, meaning it formed very shortly after Mars itself came into being. After an impact event launched it from Mars’ surface, ALH84001 had spent nearly 16 million years dancing out in space before crash-landing in Antarctica somewhere around 13,000 years ago.

In 1996, ALH84001 found its way into the spotlight when NASA scientist David McKay reported a shocking discovery: this meteorite may hold evidence of ancient microbial life on Mars.

The carbonate disks found in ALH84001, rimmed with black magnetite rings. Image: Thomas-Keprta et al. (2009)

The carbonate disks found in ALH84001, rimmed with black magnetite rings.
Image: Thomas-Keprta et al. (2009)


While examining the meteorite, McKay’s group found that ALH84001 contains flat carbonate disks rimmed with rings of tiny magnetite crystals. Magnetite is a commonly occurring iron oxide that is a natural magnet. Terrestrial magnetite is known to form in igneous and metamorphic rock when under pressure in high temperatures. However, some magnetite is of biogenic origin – it is created by living organisms.

In 1975, Richard Blakemore discovered a group of magnetite-producing bacteria that he named “magnetotactic bacteria.” Magnetite derived from magnetotactic bacteria is very distinct; they produce very fine (as small as 0.000000005 meters!) magnetite crystals bound by intracellular membranes. These tiny organelles are called “magnetosomes.”

The magnetosomes of magnetotactic bacteria are aligned in chains that act like a bacterial compass needle – they orient the bacteria into perfect alignment with the Earth’s geomagnetic field. The bacteria use this process, called “magnetotaxis,” to narrow their search for an ideal growing environment.

Interestingly, magnetotactic bacteria exist in numerous forms in as many varied locations around the planet. Magnetotactic cocci, rods, vibrios, spiriella, and even multicellular forms have been found in diverse aquatic environments, from oceans to lakes to rice paddies. The only things these tiny, living magnets seem to have in common is that they are all Gram-negative, contain magnetosome chains, and live in watery habitats.

A transmission electron micrograph of a magnetotactic bacterium. The dark spheres are the magnetosomes, lined up in a chain along the bacterium's axis. Image: Nature Education

A transmission electron micrograph of a magnetotactic bacterium. The dark spheres are the magnetosomes, lined up in a chain along the bacterium’s axis.
Image: Nature Education

The magnetite from magnetotactic bacteria is so finely, purely, and consistently produced, that to date, no lab has been able to synthesize magnetite of the quality made by magnetotactic bacteria. However, scientists have been able to use both magnetotactic bacteria and isolated magnetosomes in a variety of medical and scientific applications.


That magnetite was found in ALH84001 is in itself not very exciting; magnetite is made all the time near terrestrial volcanoes and hydrothermal vents. In fact, about 75% of the magnetite crystals ringing ALH84001’s carbonate disks may have been produced by those same processes. What excited the scientific community were the unique chemical and physical properties of the remaining 25% of the crystals.

These magnetite crystals are chemically pure and very fine, measuring a tiny tens of nanometers in size. In terms of size, shape, purity, and magnetic properties, these crystals match the characteristics of magnetite produced by terrestrial magnetotactic bacteria – the same properties that neither humans nor geological processes could imitate.

Many experts therefore believe that these magnetite crystals are a Martian biosignature: a physical or chemical marker of the presence of life. If this is true, these Martian bacteria are the earliest forms of life known to man.

A side-by-side comparison showing the similarities between magnetite crystals found in ALH84001 and those produced by the Earth magnetotactic bacterium strain MV-1. Image: Kathie Thomas-Keprta, NASA Johnson Space Center

A side-by-side comparison showing the similarities between magnetite crystals found in ALH84001 and those produced by the Earth magnetotactic bacterium strain MV-1.
Image: Kathie Thomas-Keprta, NASA Johnson Space Center


Whether or not these magnetite crystals were actually made by ancient Martian magnetotactic bacteria is a subject of hot debate. Other potential Martian biosignatures exist, though none so definitive as a mineral of biogenic origin. Methane found in Martian rock samples may imply active biological processes are taking place on Mars, perhaps just below the planet’s surface.

Further, analysis of the carbonate disks in ALH84001 showed that they were formed during what is known as the Noachian epoch on Mars, when high numbers of asteroid and meteorite impacts formed the oldest Martian surfaces that exist today, and water was possibly an abundant resource on Mars. These disks precipitated 3.9 billion years ago in a shallow, sub-surface watery environment near a temperature of 18°C. This means that this magnetite was produced in an environment similar to ones where some terrestrial magnetotactic bacteria are found.

Some experts believe that, rather than being made by bacteria, the magnetite may have been produced by the geological process of thermal decomposition, as often seen on Earth. However, experiments have shown that none of the currently proposed scenarios for geological production of these crystals could have resulted in magnetite crystals with these properties. This doesn’t prove that the crystals definitely resulted from a biological process; it just means that we still can’t rule out the possibility that they did.


It may not be a giant face on the surface of Mars, but ALH84001 has brought us closer to finding extraterrestrial life than ever before. Will our search for neighbors somewhere in the cosmos prove fruitless, or miraculously reveal that we are not alone in this vast universe? We may never know for sure, but at least the clues hidden in ALH84001 have given mankind a real reason to hold on to hope, and Congress a real reason to give NASA funding. Perhaps that’s a big enough miracle in itself.

Jurassic Pests

Drs. Sattler and Grant treat the sick triceratops in the film adaptation of Jurassic Park (1993).   Image:

Drs. Sattler and Grant treat the sick triceratops in the film adaptation of Jurassic Park (1993).

When considering the practical issues surrounding opening Jurassic Park, several obvious areas of concern immediately come to mind: finding an isolated chain of tropical islands, building immense electric fences, hunting versus feeding regimens, and kitchen-oriented velociraptor escape plans. Equally as important as containment of the island’s inhabitants, however, is the prevention of dino diseases that could quickly put the park out of business.

Fortunately for Jurassic Park’s veterinarians, we already have a pretty good sense of some of the major diseases that could afflict the park’s main attractions. Through careful analysis of the fossilized clues dinosaurs left behind the last time they roamed the earth, paleobiologists have discovered that the Land Before Time was crawling with the microbial ancestors of many bugs that plague tropical regions today.

A sauropod coprolite, with external surface above and cut and polished surface below.  Source: Graham Young, The Manitoba Museum

The prettiest poo you’ll ever see: a sauropod coprolite, with external surface above and cut and polished surface below. 
Image: Graham Young, The Manitoba Museum


Dinosaurs were kind enough to leave ample clues as to what plagued them in the form of coprolites – Latin for “dung stones” and English for fossilized dinosaur poo. Left behind in the coprolites are indicators that ancient forms of the very same worms and protozoa that infect humans and other modern vertebrates were also a problem for dinosaurs.

Though remains of adult parasitic worms did not survive the intervening years, fossilized eggs from trematodes, commonly known as “flatworms” or “flukes,” and three types of nematodes, or roundworms, were found in coprolites. Preserved cysts of the protozoan Entamoeba antiquus, a cousin of the modern-day gastrointestinal parasite Entamoeba histolytica, have also been seen entrapped in coprolites.

Though their eggs and cysts were shed in the dinosaur’s feces, the mature forms of all four parasites would have resided in the dinosaurs’ intestines, just like their modern-day descendants. The forms of the parasites found fossilized in the dinosaur dung are the toughest stages of these parasites’ life cycles, and help them endure the harsh environment outside their cozy host long enough to infect another individual.


Evidence of other prehistoric parasites has been found coprolites’ more popular fossil cousins, dinosaur skeletons.

For years, paleobiologists have hypothesized that lesions seen on the jawbones of Tyrannosaurus rex and its cousins were bite wounds due to fighting. However, recent investigations have shown that the lesions were actually caused by an ancestor of the protozoan Trichomonas gallinae, which is best known for causing similar disease in the beaks of modern birds.

A Tyrannosaurus rex mandible with multiple trichomonosis-type lesions (indicated by white arrows).  Image: Wolff et al., PLoS One September 2009

A Tyrannosaurus rex mandible with multiple trichomonosis-type lesions (indicated by white arrows).
Image: Wolff et al., PLoS One September 2009

In case you needed another reason to play nice with your neighbors, it turns out that the paleobiologists’ first guess actually wasn’t too far off. Though these particular bone lesions are due to disease rather than bite wounds, scientists now hypothesize that fighting and even cannibalism within tyrannosaurs were instrumental in spreading the disease.


Especially considering the park’s tropical location, of particular concern to Jurassic Park’s vets are vector-borne diseases, which are transmitted from host to host by another living organism. During the Cretaceous period (around 120 million years ago), many insects that would be familiar to us today made an appearance, bringing with them diseases that evolved to be carried by these new species.

The most prevalent vector-borne diseases are spread by blood-feeding arthropods like mosquitoes and ticks. Dinosaurs had very tough, thick hides composed of tuberculate scales, which sit next to each other but don’t overlap. Like biting insects feed off of large reptiles today, paleobiologists believed their ancestors likely fed from dinosaurs by biting the bits of skin exposed between scales.

This mosquito trapped in amber still contains the blood from its last meal in its stomach.  Source: Didier Desouens

This mosquito trapped in amber still contains the blood from its last meal in its stomach.
Image: Didier Desouens

If any bugs playing taxi to a pathogen found themselves stuck in tree sap, the fossilized sap – called amber – would freeze the bug and the contents of its gut, providing modern-day scientists with a snapshot of what that bug ate. Looking at amber-imprisoned mosquitos and sand flies under a microscope has revealed that (fortunately for Jurassic Park’s geneticists), not only did these insects feed on dinosaurs, they carried with them several familiar diseases.

Leishmania and malaria are two vector-borne protozoan parasites found in amber-preserved sand flies and mosquitoes, respectively. Today, there are a whopping 198 million cases of malaria worldwide every year, most occurring in sub-Saharan Africa; leishmania comes in behind it with 1.3 million cases annually.

Though it’s not completely clear how the disease progressed in dinosaurs, in humans, leishmania takes several different forms, from a painful, disfiguring skin disease to an often-fatal enlargement of the spleen and the liver. Malaria infects and destroys red blood cells, causing severe anemia, and, in severe cases, neurological problems and pregnancy loss. It’s likely these diseases manifested in similar ways in ancient reptiles.


With many of the diseases that burdened dinosaurs in their heyday still around today, Jurassic Park’s chief veterinarian has a lot to look out for. Fortunately for him, his charges gave him plenty of advance notice of what to expect – about 200 million years’ worth.

The Andromeda Strain

Spain's Rio Tinto is famous for its bright red hue and very acidic waters (pH 2.2). The acidity is thought result from the extremophilic bacteria living in the water. Image: Montuno, Flickr

Spain’s Rio Tinto is famous for its bright red hue and very acidic waters (pH 2.2). The acidity is thought result from the extremophilic bacteria living in the water.
Image: Montuno, Flickr

In Michael Crichton’s sci-fi thriller The Andromeda Strain, a military satellite crash-lands outside a sleepy Arizona town. After the towns’ citizens die suddenly of a mysterious illness, it becomes clear that the satellite was knocked out of orbit by a meteoroid contaminated with a deadly extraterrestrial microbe.

While this premise makes for a great story, how plausible is it? Can microbes survive a trip through space?


In order to survive space travel, a microbe would need to be very hardy.

Some microbes have the ability to go into a dormant state and shield themselves with a tough endospore. As spores, microbes can survive extreme conditions until they end up in a place where they are better suited to grow and reproduce.

Some microbes don’t just survive in harsh conditions such as very high or low temperatures, pHs, and pressures, but thrive in them. These microbes are called extremophiles, meaning “lover of extremes.” Extremophiles are found on Earth near deep-sea vents, in an asphalt lake, and in every other unlikely, inhospitable environment imaginable. Deinococcus radiodurans, for example, has no problem being pounded with gamma radiation. To each his own.

Considering the extreme conditions of outer space, extremophiles and spore-forming microbes are the most likely to survive space travel.


For an extraterrestrial pathogen to wipe out humanity, it must first find a way to leave its home planet without being killed in the process. Meteoroids from planets are released into space by an impact event, in which a very large object hits a planet with such force that it catapults pieces of that planet out of orbit.

An impact event, like this artists's depiction of a comet crashing into a planet, would cause the release of meteroids into outer space. Image: NASA

An impact event, like this artists’s depiction of a comet crashing into a planet, would cause the release of meteroids into outer space.
Image: NASA

There are three main forces associated with this kind of launch that a microbe would have to survive: acceleration, compression shock, and heating. In order to release from Mars, for example, a piece of rock would be accelerated at a rate of about 390,000 times the acceleration due to earth’s gravity, experience shock of up to 385,000 psi, and be heated to anywhere from 100 to 660 °F.

Needless to say, most of the organisms tested were killed during simulations of launch conditions. However, experimental evidence suggests that anywhere from 5 to 5 million spores of some organisms could still survive per kilogram of rock.

As this kind of impact can launch up to 1 billion kilograms of rock into space, this could still leave a very large number of living microbes to go off and wipe out intelligent life on an unsuspecting planet.


The earth is protected from cosmic rays by its magnetic field. Outside the earth's magnetosphere, however, ionizing radiation can do permanent damage to an organism's DNA. Image: NASA

The earth is protected from cosmic rays by its magnetic field. Outside the earth’s magnetosphere, cosmic radiation will not turn you into the Human Torch; it will give you cancer.
Image: NASA

The journey through outer space would prove the most arduous of the challenges facing a microbe hoping to colonize a new planet.

Outside of the protective magnetic fields that surround a planet, objects traveling through outer space are bombarded by high-energy ionizing radiation from galactic sources and the sun.

Despite comic books’ assertions to the contrary, getting hit by cosmic rays will not turn the bugs into superbugs. These stray X-rays, gamma rays, and other harmful particles damage an organism’s DNA. Though there are limits to these abilities, many extremophiles have developed ways to prevent or even repair DNA damage due to radiation.

For microbes below the surface of the meteoroid, radiation, microgravity, and extreme temperatures are not nearly as alarming as desiccation, or the lack of water caused by extreme vacuum. Without water, even the hardiest of organisms can’t perform basic processes required for it to function, leading to its slow but inexorable degradation.

Because of the dangers of desiccation, a microbe would have to take a relatively short journey if it was to survive outer space.

Austrian astronomer Edmund Weiss's 1888 depiction of the 1833 Leonid Meteor Shower.

Austrian astronomer Edmund Weiss’s 1888 depiction of the 1833 Leonid Meteor Shower.


Compared to the merciless battering it takes during launch and the bleak, unforgiving landscape of space, the forces involved in landing are relatively easy for a microbe to survive.

When a meteoroid comes close enough to Earth’s gravitational pull, it enters the upper atmosphere at speed of 10-20 km/s. Though friction heats and melts the surface of the now-meteor, as it takes less than a minute to fall to the surface of the earth, the heat doesn’t penetrate beyond the outer few millimeters of rock.

Assuming the meteor is big enough, this means the heat of re-entry would only kill microbes near the surface, which probably did not survive the journey up to this point, anyway.

The meteor is broken into fragments in the lower atmosphere and scattered over a wide area. This actually is a good thing for any microbes hoping to make Earth their new home, since it increases the chance they will land someplace nice to grow.


In order for a worldwide outbreak of the disease – a pandemic – to occur, even more chance is involved.

The extraterrestrial microbe would have to happen to land somewhere where it can both grow happily and be found by people. A contaminated meteorite that lands at the South Pole is unlikely to spark the zombie apocalypse unless the zombies in question are also penguins.

The microbe would also have to be both infectious and harmful to people. Though a microbe humans haven’t evolved to deal with is more likely to cause disease, it is far from certain that an extraterrestrial microbe would be pathogenic.


While it’s not impossible for an extraterrestrial microbe to land on Earth and begin obliterating entire towns, the sheer number of unlikely events involved makes the chances of its happening vanishingly small. An alien pandemic-Armageddon actually happening would be akin to the Universe declaring, “I hate you, Planet Earth!”

The Curious Case of Tiny Tim Cratchit

Norman Rockwell’s illustration of Tiny Tim and Bob Cratchit for the cover of the Saturday Evening Post, 1934.

Though it’s been a little more than a century and a half since Charles Dickens published his beloved Christmas tale of compassion and karmic retribution, the unstated cause of Tiny Tim Cratchit’s crippling illness still sparks debate among scientists and medical doctors who have had a little too much scotch at holiday parties.

Though a definitive diagnosis has yet to be made for Tiny Tim’s condition, several promising theories have been created to explain what ails him.


Here is what we know from the text of Charles Dickens’ novella:

  1. Tiny Tim is exceptionally small for his age (hence the nickname), and most likely has a growth defect.
  2. Bob Cratchit occasionally carries his son, suggesting Tim suffers from muscle fatigue.
  3. Tim uses a single crutch, indicating the disease is unilateral – only one side of his body is affected.
  4. Tiny Tim’s illness could be treated using the medical knowledge and technology available in Dickens’ London, as Scrooge’s intervention prevents his death.
  5. If left untreated, Tiny Tim’s disease would have killed him within a year.


One popular theory is that Tiny Tim had polio, a paralytic disease caused by a poliovirus infection. Polio can cause paralysis if the infection spreads to the central nervous system and replicates in motor neurons, the cells responsible for sending signals for movement from the brain to the muscles.

Iron Lungs in the Hynes Memorial Hospital in Boston, 1955. Iron lungs kept polio victims breathing despite the paralysis of muscle groups in the chest. Image courtesy of the FDA

Iron Lungs in the Hynes Memorial Hospital in Boston, 1955. Iron lungs kept polio victims breathing despite the paralysis of muscle groups in the chest.
Image courtesy of the FDA

Polio, however, is the easiest diagnosis to refute; there is no cure for polio, and the supportive therapies required to keep Tiny Tim alive while his body fought the disease were not available at this point in history.


Dr. Donald Lewis proposes Tiny Tim suffered from Type I distal renal tubular acidosis, or dRTA. dRTA occurs when the body doesn’t excrete acids properly because the kidneys cannot efficiently remove them from blood. As a result, acids build up the blood stream, causing low levels of potassium, kidney stones, calcium deposits in the kidney, and bone demineralization.

This is a promising diagnosis, as it fits nearly every symptom presented by Tiny Tim. Bone demineralization, which causes rickets in children, results in stunted growth, muscle pain, and skeletal deformity. The low levels of potassium, also called hypokalemia, can cause muscle weakness, pains, cramps, and flaccid paralysis. Calcium deposition in the kidney, particularly when combined with skeletal muscle breakdown due to hypokalemia, causes kidney failure and is fatal if left untreated.

dRTA was also treatable at the time; tonics containing fish oil and the Victorian equivalent of Alka-Seltzer would give Tim the basic compounds and Vitamin D needed to counteract the buildup of acid in his bloodstream and the problems that acidity causes.

Many of the characteristics of dRTA fit the illness crippling Tiny Tim with one exception: Tim’s more obvious symptoms are always bilateral when caused by dRTA, meaning they would affect both sides of the body. However, Dickens’ story suggests Tiny Tim’s disease is a UNI-lateral one. Thus, dRTA probably isn’t what was ailing Tiny Tim.

Children of Oklahoma drought refugees on highway near Bakersfield, California, 1935. The young girl on the right has "bone tuberculosis," or Pott's Disease. Photo by Dorothea Lange

Children of Oklahoma drought refugees on highway near Bakersfield, California, 1935. The girl on the right has “bone tuberculosis,” or Pott’s Disease.
Photo by Dorothea Lange


Dr. Russell Chesney disagreed with Dr. Lewis’s theory, so much so that he wrote a commentary in the American Journal of Diseases of Children in response to Lewis’s paper titled simply, “Bah! Humbug!” Chesney proposes instead that Tiny Tim suffered simultaneously from Pott’s disease and rickets.

Pott’s disease is a special manifestation of tuberculosis in which the infection spreads to the spine, causing the discs between vertebrae to break down and completely collapse. Eventually, it can cause spinal cord compression and paralysis of one or both of the legs.

Rickets is caused by deficiencies in necessary minerals like Vitamin D, phosphate, and calcium, and can result from poor nutrition and lack of exposure to sunlight.

Chesney puts particular emphasis on considering the environmental conditions of Victorian London when attempting to diagnose Tim. Factors such as the thick, coal-polluted air, the high population density in tenements, woeful nutrition in lower income households, and the general filthiness of the city at that time made London prime real estate for infectious disease and overall poor health. Approximately 50% of Victorian London’s population had some level of tuberculosis infection, and rickets afflicted nearly 60% of its children.

If helped by Mr. Scrooge, Tiny Tim could have received better food, cod liver oil, and more fresh air, exercise, and sunlight to help him recover from rickets. Vitamin D deficiency also worsens tuberculosis, in large part because it weakens the innate immune response to the disease. Thus, treating this deficiency could have helped Tiny Tim fight his tuberculosis infection, as well.


Though tuberculosis was difficult to treat at this time, Dr. Chesney’s is the most likely of the hypotheses presented. This scientist’s diagnosis, however, is that Tiny Tim Cratchit suffered from an acute metaphor for societal neglect compounded with a particularly potent manifestation of Dickensian pathos.