Adventures in digestion

experiments on digestionIn the 1820s a young Canadian, Alexis St Martin, was shot in the stomach by a musket-ball.  He recovered from the injury, but the wound never healed.  His doctors discovered that this opening (known clinically as a fistula) communicated directly with his stomach.  In 1827 he had put up with this external opening to his gut for two years, and his case was reported in The Medico-Chirurgical Review, which stated

that the aliment taken into the stomach quickly escaped by this fistula, unless it was kept well defended by pad and compress—that the health of the young man was excellent, the appetite good, the digestion perfect, the body active, and the individual capable of every species of labour and exercise. He could, at pleasure, disgorge the aliment from his stomach, by merely removing the pad by which the fistula was closed.

An army surgeon, Mr Lovell, had looked after St Martin during his recovery, and saw this as an excellent opportunity to conduct some experiments on the subject of digestion.

“When,” says Mr. L. “I removed the pad, it often happened that the internal membrane of the stomach was protruded in the form of a half-blown rose, and resembling that in colour. The patient (if patient he could be called) was able to reduce this herniary protrusion by slight pressure, and without any pain. When San Martin was lying on his right side, I could see into his stomach, perceive the

St Martin's stomach
St Martin’s abdomen with fistulous opening to stomach

movements of that organ, and follow, to a certain point, the different stages of digestion. I sometimes introduced water into his stomach, by means of a funnel, and solid food by means of a spoon. Afterwards I could draw them out by the aid of a syphon. I was also able to introduce pieces of meat, raw or dressed, as well as other species of aliment, tied by threads, the ends of which were kept outside. By these means I was enabled to make many curious experiments on the time necessary for the digestion of various nutritive substances. One time I introduced as a plug, or obturateur, a piece of raw beef. At the end of five hours, all that part which had gone inside of the stomach, was completely digested, and had disappeared. The division was as smooth as if it had been cut off by a knife. Every second or third day, a wine-glass full of gastric juice could be drawn off from the stomach, without any injury or pain to San Martin.”

For his first experiment, Mr Lovell introduced several items of food, secured with cotton threads so that they could be withdrawn from the stomach at will:

a piece of alamode-beef strongly spiced—a piece of raw corned beef—a piece of fat bacon—a piece of fresh raw beef — ditto boiled—a piece of bread—a piece of raw cabbage stalk. After they were introduced into the stomach, San Martin continued his domestic occupations, as usual, within doors. In one hour after the introduction of the above materials, they proceeded to examine them. The cabbage stalk and the bread were about half-digested—the animal food had undergone no sensible change. All the articles were forthwith returned into the stomach. At the end of two hours, the cabbage, bread, and bacon were entirely digested—the other aliments were little altered. At the expiration of three hours, the alamode beef was partly digested—the raw and corned beef was a little macerated on the surface, but its texture was nearly entire. The fluids of the stomach were somewhat rancid to the taste and smell. San Martin complained of some sense of uneasiness in the chest. At five o’clock he suffered much in his stomach—experienced a lassitude and general weakness, with head-ache. On drawing out the two bits of beef, they were found in nearly the same state as they were two hours previously—but the fluids of the stomach were still more rancid and acrid. The sufferings of San Martin prevented the re-introduction of the materials.

I suspect most of us would have felt a bit queasy if we had to swallow a cabbage stalk, with or without a gaping wound to the stomach.  The first experiment was terminated and St Martin allowed to recover.  But less than a week later our game Canadian was back for more:

On the 7th of August, at 11 o’clock in the forenoon, the tube of a thermometer was introduced into the stomach. In five minutes the mercury stood at 100° of Fah. and continued at that standard. By means of a gum-elastic syphon, one ounce of clear gastric juice was drawn off, into a phial capable of holding three ounces. A small piece of boiled beef was immersed in the fluid. The bottle was well corked, and placed in a temperature of 100°. In about 40 minutes the digestion had evidently commenced on the surface of the meat. At 50 minutes, the fluid in the phial became opake and cloudy. The fibres of the meat began to be disengaged, and in one hour chyme seemed to be forming. At 1, p.m. the muscular fibres had diminished one half. At 5 o’clock, very few remained—and at 7, there was scarcely any visible trace of muscle. At nine the whole substance was completely dissolved. The solution had now the appearance of whey, and shortly afterwards a precipitate resembling the meat, in colour, fell to the bottom of the phial.

Mr Lovell had the presence of mind to conduct a control experiment:

On the same day, and at the same hour, a piece of meat, exactly the same size and kind as that placed in the phial, was introduced into the stomach, with a thread attached to it. At the end of one hour, it presented nearly the same appearance as the piece in the bottle. At one o’clock, the thread came away, the meat appearing to have been entirely dissolved. The process in each case was the same, for the first hour; but afterwards, the meat was much more quickly digested in the stomach than in the phial. In both cases, the digestion commenced at the surface of the meat, and seemed stationary there for a certain time. In the phial, gentle agitation seemed to quicken the solution, by presenting new points of surface for the contact of the gastric juice.

A fourth experiment followed, in which chicken was used instead of beef.  The results were unremarkable: the chicken was digested.

The young Canadian was now tired of these experiments, and departed for his native place.

I have a suspicion that he was a little more emphatic about it than this sentence suggests.

These experiments are curious. They are not different from what we might naturally expect,

i.e., we learned nothing new.

and they shew that it is to the gastric juice we owe the mysterious process of digestion, and not to any action of the muscular fibres of the stomach. These muscles merely move forward the digested strata to the pyloric orifice, as was well shewn by the experiments of Dr. Philip in the stomachs of rabbits. The effects of indigestion were satisfactorily demonstrated, when the farrago of various substances were introduced into San Martin’s stomach.

To the satisfaction of the experimenter, maybe, but not to that of his unfortunate subject.  The article concludes that deliberately giving an experimental subject indigestion proves that you shouldn’t, er, give yourself indigestion:

This experiment affords a useful lesson to the gourmand, who mixes a dozen of different kinds of viands in his stomach, regardless of the different degrees of digestibility in different substances.

Postscript: Alexis St Martin was also the subject of a much longer series of 238 experiments, conducted by the US Army surgeon William Beaumont, who had treated the young man for his original injury.  In 1833 he published his results in an important book, Experiments and  Observations on the Gastric Juice and the Physiology of Digestion.

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