Being a self-experimenter is not for the faint hearted. You have to be willing to do things which most people wouldn’t even imagine. All this just to prove oneself right to the world. In today’s post which is a part of the DOCTORS & SCIENTISTS WHO SELF EXPERIMENTED we see a man who took this to another level.
Lazzaro Spallanzani was born on 10thJanuary 1729 in Scandiano, Italy. He was an Italian catholic priest along with being a biologist and a physiologist who took special interest in studying the bodily functions. In 1754, at the age of 25, he became professor of logic, metaphysics and Greek in the University of Reggio. In 1762 he was ordained as a priest. Spallanzani read voraciously but was a sceptic, hesitant to believe anything that he could not prove himself. He has made enormous contributions to science and medicine but I am choosing just one of those experiments because you have to read it to actually believe it.
Spallanzani started his experiments on digestion in 1776. He was teaching at the university of Pavia at the time. The first time he experimented, he chewed a loaf of bread and spat it into a bag. He then placed the bag in his mouth and swallowed it with a glass of water. The bag was made of linen. The wait overnight was obviously a nervous one for him because he didn’t know if the bag would come out or not. The next morning, when he went to empty his bowel, to his surprise and relief he passed the linen bag without any problem. What was more interesting to him was that the bread was gone which meant that the digestive juices had digested it through the bag!
Having successfully proved to himself that digestion was indeed a process done by the digestive juices, he now wanted to prove the same to the world. He then followed this with a number of other tests. Next, he enclosed the bread with a triple layer of cloth bag and swallowed it. When he passed stools the next day, the bread came out along with the triple layered bag without any change which meant that the digestive juices could not appropriately reach the bread within.
He then replaced the bread with meat. He found that if he pre-chewed the meat before putting it in the bag and swallowing it, the bag came out empty. If he used only a single or double layered bag, they would come partially digested.
Researchers are never happy with the results. Next Spallanzani wanted to know how long it would take for food to get completely digested. So, he took a semi digested piece of meat (meat which he chewed first), put it into a bag and swallowed. Sometimes it would come back partially digested. So, he would again take that partially digested meat piece, put it in a bag and swallowed it again.
Usually the bag came empty after the food was passed for the third time. In my research I couldn’t find whether he used a new bag every time or the same one. I am sure you are wondering the same.
Next, he wanted to test whether it was the digestive juices what aided the digestion of the food or was it the stomach muscles which digested them. So, he chewed some veal, put it in a wooden tube with perforations. The next day when he sat on his commode, the wooden tube dropped out with a thud, without any meat. This revealed that the stomach doesn’t digest food by grinding or crushing by the help of stomach muscles.
Before finishing his self-experiments, Spallanzani wanted to definitively prove that the digestion of food occurred mainly in the stomach and not the intestines. So, what he did for his final experiment was that, he swallowed a tube containing some beef. He then waited for a couple of hours knowing well that food remains in the stomach for about 4 hours before going down. Then he stuck his finger down his throat and vomited the tube back up along with a large quantity of gastric juice. It was a very painful experience for him. He noted that the beef in the tube had already turned soft and gelatinous which proved to him that the digestion was occurring in the stomach.
Next, he kept a fresh piece of meat in the gastric juice that he had vomited. In another tube he kept an additional piece of meat in water. After 3 days, the meat in the gastric juice tuned into oozy slime while the meat in the water began to rot but was still whole. This conclusively proved his theories.
He couldn’t continue with his experiments because he couldn’t handle the vomiting anymore. According to the Electrified Sheep, he says-
The disagreeable feelings occasioned by the act of vomiting, the convulsions of my whole frame and more especially of my stomach, that continued for several hours after it, left upon my mind such a repugnance for the operation, that I was absolutely incapable of repeating it, not withstanding my earnest desire for procuring more gastric liquor.
Thanks to him, researchers learned that digestion is a chemical process.
Along with this he also discovered that animal reproduction requires both semen and ovum.
Spallanzani is also famous for extensive experiments on the navigation in complete darkness by bats, where he concluded that bats do not use their eyes for navigation in total darkness, but some other sense
He died of bladder cancer on 12thFebruary 1799 in Pavia. After his death, his bladder was removed for study by his colleagues, after which it was placed on public display in a museum in Pavis where it remains to even this day.