578 ANAPHYLAXIS IN RELATION TO INFECTION AND IMMUNITY 



well known that animals may be sensitized by feeding them proteins 

 not usually present in their diet, as by giving guinea-pigs horse serum or 

 the flesh of other animals. 



Among the commoner examples of this form of allergy or anaphylaxis 

 may be mentioned : 



1. Horse asthma, observed among those persons who are seized with 

 sneezing, cough, dyspnea, coryza, and prostration when they come near 

 horses, as in a stable or when driving. 



2. Hay-fever, first ascribed to the pollen of plants by Elliotson in 

 1831, and thoroughly studied by Dunbar. Wolff-Eisner was the first 

 to regard the reaction as a phenomenon of hypersensitivity or anaphy- 

 laxis. Individuals subject to hay-fever show a uniform series of symp- 

 toms at certain definite seasons, either in the early summer or in autumn. 

 These are a reddening, swelling, and watering of the eyes, sneezing, a 

 sore feeling in the throat and larynx, and asthmatic disorders. The 

 instillation into the eye of a 1 per cent, solution of pollen in physiologic 

 salt solution is usually sufficient to elicit a typical attack. Certain 

 persons are susceptible to various weeds, and each usually knows the 

 particular weed to avoid. In hay-fever we have the most marked in- 

 stances of extreme hypersensitiveness; persons may be seized with an 

 attack when some distance from the particular weed in question. Similar 

 phenomena are occasionally observed among workers in satinwood 

 (satin wood dermatitis) . 



3. Certain foods, such as egg-albumen, buckwheat (phagopyrismus) , 

 pork, oysters, clams, lobster, cheese, and various fruits, such as straw- 

 berries, gooseberries, and even vegetables, may act as poisons when in- 

 gested by persons who are hypersensitive to them. The symptoms vary 

 from a feeling of "indigestion" and "heartburn" to severe diarrhea, 

 vomiting, asthma, and the development of an itching urticarial rash. 

 In some instances it has been possible passively to sensitize guinea-pigs 

 against the particular protein by injecting a few cubic centimeters of the 

 patient's serum. Thus Bruck succeeded in doing this with the serum of a 

 person hypersensitive to pork. In many instances it is possible to 

 demonstrate the hypersensitive state by rubbing a small amount of the 

 substance into a superficial abrasion of the arm, as in the example of 

 horse serum anaphylaxis illustrated in Fig. 121, and, as shown by 

 Thayer, in a case of buckwheat hypersensitiveness. It may also be 

 demonstrated in hay-fever by making conjunctival instillations of the 

 particular pollen. 



4. Certain drugs, such as iodoform, iron citrate, and even atropin, 



