Depart.] natural sciences op Philadelphia. 19 



October, 



I. Anatomy. 



Dr. Schmidt, with reference to a communication made by him at a meeting 

 held in September, exhibited two livers of sheep, in order to show the method 

 pursued by him, in making his injections. It is as follows : 



The liver is placed in a basin from which the air is exhausted. The appara- 

 tus is so arranged, that, when desired, a communication can be established with 

 the blood vessels. In making an injection, the pressure is exerted chiefly by the 

 weight of the fluid, which is in a column about six inches in height. So soon 

 as the injection is made in this way into the hepatic duct, the fluid used issues 

 from the lymphatics. The injections are also made in a second manner, the 

 organ not being kept in a vacuum. In this, the lymphatics and their glands 

 are also injected, though the pressure of the air prevents the liquid from flow- 

 ing from the opened mouths of the lymphatic vessels, as it does when this 

 pressure is removed. 



In both the preparations exhibited by Dr. Schmidt, one having been injected 

 in a vacuum, the other not, in the way just described, the lymphatic vessels, 

 and also their glands, were seen injected. 



II. Physiology. 

 Dr. Morris read the following paper: 



Remarks on the Digestive Principle. By J. Cheston Morris, M. D. 

 In the course of some observations offered to the Department at the session 

 of June 7th, 1858, on the subject of endosmose, I suggested the hypothesis that 

 during digestion a watery fluid was secreted from the gastric mucous mem- 

 brane, containing a principle which was capable of splitting, or undergoing a fer- 

 mentative change, so as to produce lactic acid and so-called pepsin. I now have 

 the pleasure of laying before the Department the facts necessary to substantiate, 

 that hypothesis. 



When a very dilute solution of ov-albumen is exposed to the air at a moder- 

 ate temperature for several days, it becomes cloudy and has a slightly acid 

 reaction. This change is hastened if air is forced through the solution from 

 time to time. If a small portion of this be added to fresh milk it will cause 

 coagulation of the latter in a short time ; boiling the solution previously, dimin- 

 ishes this property. When a thin portion of coagulated albumen is placed in 

 the solution at a warm temperature, it is dissolved in the course of a few hours ; 

 if the solution be previously boiled, no such change occurs. When the solution 

 is distilled, the distillate yields a white curdy precipitate with nitrate of silver, 

 soluble in an excess of ammonia. 



The above facts correspond so closely, as far as they go, with the properties 

 of the gastric juice that I have no hesitation in stating my belief that they af- 

 ford the explanation of the mode of formation of the latter. We have, in 

 effect, an albuminous fluid in the stomach, placed under appropriate circum- 

 stances as regards oxygen and temperature for the occurrence of fermentative 

 changes ; and if by imitating these conditions out of the body we produce 

 analogous results, we have the strongest reasons for believing that the causes 

 and mode of operation are the same in the living body. 



The foregoing experiment offers also a satisfactory solution of the apparently 

 discrepant views held by different investigators as to the digestion of azotised 

 food. It becomes no longer difficult to comprehend that the gastric juice, the 

 pancreatic fluid, and the intestinal secretion, as well as decomposing albuminoid 

 matters, may all possess the power of causing a solution of coagulated albumen, 

 &c; inasmuch as a splitting of an element common to them all, viz. albumen, 

 gives rise to an acid, (probably lactic,) and a digestive principle. I regret 

 that I have, not been able to make an ultimate analysis of the substance obtained 

 by evaporating the solution above mentioned to dryness at a low temperature. 

 These experiments also set at rest the mooted question of the free acid of the 



1859.] 



