IMMUNOLOGY. IMMUNITY AND IMMUNIZING AGENTS 255 



even mineral. The sensitization or anaphylactic reaction phenomena 

 are extremely variable in kinds as well as in degree. The following is a 

 brief summary of the subject: 



Disease is nothing more nor less than an anaphylactic reaction to the 

 proteins of the causative agents, as bacteria and protozoa. The reactions 

 indicate that nature is endeavoring to overcome the toxins formed, de- 

 veloped or generated. It is presumed that no one will take a disease 

 unless first sensitized to the specific causative agent. What is generally 

 known as the incubation period in disease corresponds to the sensitiza- 

 tion .period in anaphylaxis. Recovery from disease simply means that the 

 characteristic reaction (as manifested by the symptoms) has been suc- 

 cessful. If death is the outcome, it means that the reaction was exhausted, 

 paralyzed or broken down. 



Hypersusceptibility to certain foods, more especially to roe, fish, 

 shellfish, eggs, milk, cheese, rhubarb, strawberries, tomatoes and cereals, 

 is fairly common. The symptoms usually appear soon after eating and 

 vary in kind as well as in degree, depending upon the nature of the food 

 and the degree of susceptibility to it. There may be urticarias, erythemas, 

 prickly heat, spasms, asthmatic conditions, respiratory difficulties, 

 fever, gastrointestinal disturbances and occasionally sudden and complete 

 collapse. Physicians have noted that eczema is frequently caused by 

 certain foods, as excess .of fats and starch. The so-called cyclical 

 vomiting of children is supposed to have its origin in food susceptibility, 

 associated perhaps with an inherited neurasthenic condition. 



It is theoretically suggested that man was originally hypersensitive 

 to all foods and as a result of the anaphylactic reaction the specific anti- 

 bodies or protective bodies were gradually developed, finally establishing 

 full prophylaxis toward those substances which we now recognize as 

 harmless and wholesome foods. The reason why we cannot use the 

 deadly night-shade, or nux vomica, or aconite, or tobacco, as foods is 

 because we are still in a state of hypersusceptibility toward these 

 plants. There are many marked racial differences in food hypersuscep- 

 tibility. The goat and the hog will thrive on vegetables which are highly 

 toxic to man. The existence of an anaphylactic reaction toward a 

 given substance, as strychnine, aconite, curara, etc., indicates an effort 

 to establish immunity. If the amount of ingested food substance for 

 which immunity is not yet established is excessive, the reaction may be 

 wholly exhausted with disastrous results. Anaphylaxis is nature's 

 warning against over-indulgence in a food for which prophylaxis is 

 not yet fully established. 



Anaphylaxis which is developed parenterally, that is by bringing 

 the reacting protein or other substance in direct physiological contact 



