FLESH MEAT A CHEMICAL EXCITANT. 99 



From the experiments with simple substances we may now pass on 

 to others, in which we introduced different combinations of ordinary food- 

 stuffs into the stomach, avoiding at the same time the act of eating. 

 We shall then see what the combined influence of the composite food 

 may be, made up as it is, of the already mentioned simple effects, and 

 learn in how far the former may be explained by the latter. 



When considerable quantities of finely divided raw flesh are intro- 

 duced unnoticed into the main stomachs of our dogs the secretion of juice 

 begins (as already stated in the fifth lecture) at the earliest, from fifteen 

 to thirty minutes afterwards. At this point I must not overlook an 

 arrangement which was used for bringing the flesh into the stomach 

 (Dr. Lobassojf). When meat is introduced piece by piece into the fistula, 

 the dog guesses what is happening, and this may naturally lead to a psychic 

 excitation of the secretion. Sometimes, it is true, the animal maybe asleep, 

 but the procedure always awakens it, and the feeding has then to be 

 finished in the waking condition. To prevent this mishap, we filled a wide 

 glass tube with the meat-pulp from the mincing-machine, introduced 

 it gently into the fistula-tube, and then pushed the flesh into the stomach 

 with a suitable rod. If the dog should wake up, it can no longer guess 

 what has happened, for the whole thing is finished, and it drops off to 

 sleep again immediately. But flesh always sets up a secretion even 

 under these conditions. This was to be expected after what has 

 been said in the beginning of the present lecture, and is easily to be 

 explained. Obviously the secretion is chiefly to be attributed to chemical 

 substances dissolved in the meat juice. Dr. Lobassoff, who undertook 

 the investigation of this question, adopted several modifications of the 

 experiment in order to test the validity of these conclusions. Thus he 

 boiled the flesh thoroughly for several days, and then saw that its 

 introduction into the stomach occasioned either no secretion at all or 

 only a very weak one. It was only necessary, however, to add some 

 Liebig's Extract to the sodden flesh in order to restore to it the activity 

 proper to raw meat. 



When analogous experiments were undertaken with bread and 

 boiled egg-albumen, that is to say, by introducing the food-stuffs into 

 the stomach in a manner which wholly excluded psychic influence, a 

 negative result, as has been said, was always obtained. They remained 

 two or three hours (as long as the observation was kept up) without 

 exciting the least trace of secretion. It is justifiable to suppose, either 

 on the one hand that these unexpected results were due to the un- 

 favourable physico-chemical condition of the material (locking-up of 

 the water), or, on the other hand, that direct chemical excitants are 

 really absent. The negative effects of fluid albumen must be borne in 

 mind, however; and, further, Dr. Lobassoff found that watery infusions 



