THE PROTEOLYTIC MECHANISM IN OPERATION 87 



tional quantity of unbroken protein. It may also result from 

 the ingestion of an unusual type of protein, notably, of course 

 of a type difficult of digestion. In general, we might expect 

 that anaphylaxis from food proteids would result with a fre- 

 quency in direct ratio to the rarity with which different proteids 

 are digested. It is confirmatory that anaphylaxis from eating 

 shell-fish, lobster, and various fishes seems to be somewhat more 

 usual than that resulting from the proteins of beef, mutton, or 

 fowl. A severe case of anaphylaxis from eating flesh of the 

 snapping-turtle has come within the observation of the writer. 

 Yet for most people the flesh of the snapping-turtle is entirely 

 wholesome as wel) as exceedingly palatable. 



It should be observed that there are doubtless idiosyncrasies 

 of individual organisms with regard to parenteral proteolysis, 

 just as there are with regard to digestion ; and this accords with 

 the familiar laboratory observation that not all animals of a 

 species suffer to the same extent from anaphylaxis under the 

 same conditions. 



In the consultation room, also, marked differences are to be 

 observed among different patients. Some patients are pecu- 

 ilarly sensitive to any protein; others are peculiarly resistant 

 to all proteins. Yet others appear to be sensitive to one protein, 

 but resistant to another. Such idiosyncrasies are, of course, quite 

 to be expected. It does not appear, however, that inherent sus- 

 ceptibility to a particular pr6tein is necessarily associated with 

 susceptibility to severe anaphylactic shock from the . sudden in- 

 troduction of a large dose of protein into the system previously 

 "sensitized." Such "sensitization," in the view here represented, 

 consists in surcharging the blood with corpuscular enzymes 

 capable of affecting rapid proteolysis of the proteins in question. 



The anaphylactic shock is probably to be interpreted as a vaso- 

 motor phenomenon. The almost instantaneous onset leaves it 

 scarcely open to question that the primary action is exercised 

 upon the vaso-motor and cardiac centers in the brain. 



The reason, presumably, why shock takes place when the pro- 

 tein is injected directly into the vein, and not when the injec- 

 tion is merely subcataneous or intramuscular, is that in the for- 

 mer case a relatively large amount of protein is brought instantly 

 in contact with the brain centers ; whereas in the latter case 

 absorption is slow and there is ample opportunity for the red 

 corpuscles to perform their regular functions of shielding the 

 brain cells by themselves absorbing the partially hydrolyzed pro- 

 tein molecules. 



The observed fact that the therapeutic administration of the 

 proteoses does not tend to produce the same anaphylactic shock 

 that is produced by the full-sized molecule of the same type (for 



