290 



SCIENCE. 



[Vol. VII., No. 164 



the play of imagination was markedly careless, 

 and uncontrolled by the inward critic, as compared 

 with the good cases in which it showed itself 

 sober and self -controlled. 



As the author says, the sources of error in such 

 observations as these are very numerous : but 

 from repeated observations by many observers, 

 carefully collated, these errors may be in a great 

 measure eliminated, and substantial results ar- 

 rived at. of whose practical bearing there can be 

 little doubt. 



OBSERVATIONS UPON DIGESTION IN THE 

 HUMAN STOMACH. 



Direct observations on digestion in the human 

 stomach have been very seldom made, as opportu- 

 nities for such cannot often occur. Those by 

 Beaumont many years ago are familiar to every 

 student of physiology, and, notwithstanding their 

 lack of completeness and their many imperfec- 

 tions, they served a very useful purpose in ex- 

 plaining many of the processes whereby digestion 

 is affected in this organ. These observations have 

 been supplemented by others ; but the results of 

 modern physiological researches have been such, 

 that renewed opportunities to make such direct 

 observations must be of great value. Such a one 

 occurred within the past year in the person of 

 Heinrich Baud, a healthy young man twenty-eight 

 years of age, into whose stomach, in consequence 

 of a stricture of the oesophagus that prevented the 

 passage of all food, a surgical opening five centi- 

 metres in length was made. The case passed into 

 the hands of Mr. A. Herzen, the well-known physi- 

 ologist, who improved the opportunity to make 

 a series of experiments upon the digestibility of 

 certain foods and upon the behavior of the gas- 

 tric juices (Kosmos, 1885, ii. 1, 4). The pepsin 

 secreted by the patient was of unusual quantity, 

 aDd, what has hitherto never been observed in 

 similar cases, or through the artificial fistulas of 

 dogs or other animals, there was a changeable but 

 often considerable quantity of bile present. These 

 circumstances, however, though complicating the 

 experiments, did not especially affect the results. 



The author's methods of experimenting were as 

 follows : a substantial meal was given to the 

 patient at 7 o'clock in the evening, and nothing 

 further was permitted to enter his stomach till the 

 next morning, when experiments at 6 o'clock were 

 begun, first upon the empty organ. After an 

 examination of the juices therein contained, there 

 was introduced the albumen from three hard- 

 boiled eggs, with two to three hundred grams of 

 water, together with three small silken nets, each 

 containing eight small pellets of albumen, uniform 



in size, and regular in shape, and which could be 

 easily withdrawn for examination. These observa- 

 tions through the fistula were made hourly, and 

 one of the nets with its contents removed. 



Remarkable and unaccountable conditions were 

 found in which the albumen remained one or even 

 two hours in the stomach without undergoing any 

 perceptible change, notwithstanding the presence 

 of ferment, with which it was impregnated. In 

 these cases the albumen pellets usually retained in 

 their substance precisely the requisite quantity of 

 pepsin for their solution, which, under favorable 

 circumstances afterwards, exactly sufficed to 

 digest them. This furnishes evidence that the 

 pepsin does not act through simple contact alone, 

 and that a given quantity of it can dissolve 

 only a given quantity of albumen, and that con- 

 sequently the pepsin, by the exercise of its diges- 

 tive activity, loses its entire potency. 



Observations directed toward the ascertainment 

 of the time required for the stomach- juices to 

 impregnate coagulated albumen showed that they 

 penetrated about one millimetre during the first 

 hour and three millimetres within the second. It 

 was also learned that the acids were much more 

 active than the pepsin in penetrating the substance. 

 This last fact furnishes a new proof of the presence 

 of a free acid in the stomach-juices. The juices, 

 however, at such opportunities as it was possible 

 to examine them, were sometimes found to be of 

 a neutral reaction. But, in order to test the 

 action of acid and ferment further, he introduced 

 at times a quantity of soda to neutralize the 

 acid ; without, however, materially affecting the 

 activity of the pepsin, although it appeared to 

 somewhat diminish it. It therefore results that 

 pepsin exerts its digestive power almost wholly 

 independently of the acid. The reverse of this, 

 as may be expected, was also found true, — that 

 the acids penetrated the albumen in the absence of 

 the pepsin, and, when the pieces of albumen were 

 small, a sufficient quantity was absorbed to digest 

 them. 



Another series of researches was made upon the 

 fluids of the stomach, from which it was found, 

 that, on the mornings after fasting, the secretion 

 usually was small, while at such times following 

 the ingestion, during the night, of milk or any 

 fluids containing alchohol, the secretion was 

 greater. During the first hours of digestion the 

 quantity held a definite relation to the volume of 

 substances introduced, while in the fifth hour the 

 quantity was always more abundant, about three 

 or four hundred grams. The first secretion of the 

 morning was in general a somewhat thick, very 

 stringy, more or less clear fluid, which resembled 

 the white of an egg ; that obtained during the 



