PATHOGENESIS 301 



of much trouble, viz., the biological inadequacy of certain 

 substances as food. The effects as they are here described show 

 that the particular extract forms a disturbing element in the 

 dog's physiological economy. We have seen that the 

 biological adequacy of food rests upon a genuine symbiotic 

 basis, a basis of give and take and not one of promiscuous 

 appropriation. This symbiotic basis which has established 

 itself in course of evolution is the true safeguard of all health 

 and progress, and, in its absence, no amount of artificial inter- 

 ference will ever adequately compensate for the lack of proper 

 relations. 



The symptoms of anaphylaxis are essentially the same in 

 man and in animals, and this shows that we are entitled, 

 broadly speaking, to draw the same general inferences as 

 regards the value of feeding and of food substances in either case. 



What generally happens is this : 



The arterial pressure is lowered, more or less, according to the 

 general intensity of the reaction, and there is intestinal congestion. . . 

 But if anaphylaxis is profound, they [the symptoms] assume a very 

 different aspect. In this case there is no pruritus. The earliest effect, 

 the first symptom, is a frequent vomiting, so prominent that in a 

 number of cases it develops at the end of ten seconds or almost imme- 

 diately after the injection even of a very small dose. This vomiting is 

 so characteristic that I have taken it as a criterion more easy to observe 

 than the fall in blood pressure. It may be said that it is never absent 

 except in some very rare cases of extraordinarily intense anaphylaxis. 

 In these the animal is immediately in such a state of prostration that 

 it has no strength to vomit. The vomit is frothy and mixed with bile; 

 sometimes it is faecal, and sometimes, in the severest cases, mixed with 

 blood : for, from the beginning, there is an intense gastro- intestinal 

 congestion. 



It is thus evident that we have here a violent eliminative 

 attempt on the part of the body, a crisis which taxes its 

 symbiotic powers. The success depends on the degree of 

 vitality and on the state of the eliminative powers ("strength 

 to vomit ") in the particular individual. 



One of the military reserve forces in Continental countries 

 (now so prominently before the world) is called the " Land- 



