CHAPTER XX 



ABDEKHALDEN'S WOEK UPON PEOTECTIVE FEK- 

 ME1STTS OF THE ANIMAL BODY 



THE recent researches of Abderhalden 1 upon the intravascular 

 digestion of foreign substances introduced into animal bodies promise 

 to have considerable bearing upon problems of immunity. Abder- 

 halden, whose work we cite chiefly from his monograph, "Die Schiitz- 

 fermente des tierischen Organismus," took as his point of departure 

 the conception that the animal body must necessarily dispose over a 

 mechanism whereby it can assimilate foreign substances which ob- 

 tain entrance unchanged into the circulation. In our section upon 

 the nature of the precipitins, especially in the discussion of Gengou's 

 conception of "albuminolysins," we have called attention to the 

 probable significance of protein antibodies as a mechanism for the 

 disposal of such foreign substances. In the bodies of the higher 

 animals in which a special alimentary system, with its many diges- 

 tive ferments, is well developed, it is most probable that the normal 

 condition of digestion is one in which the foreign substances utilized 

 for nutrition are completely split into their simpler components be- 

 fore they gain entrance to the circulation. Nevertheless, abnormal 

 conditions or accidents, such as gastro-enteric diseases, digestive dis- 

 turbances, and bacterial infections, may lead to a condition, prob- 

 ably frequent enough in ordinary life, during which such foreign 

 substances may get into the blood stream without previous cleavage. 

 The problem is to determine where and how such substances, protein 

 or otherwise, are broken up so that they may be either assimilated 

 or eliminated. We have referred in another place to the fact that 

 foreign proteins may occasionally pass through the kidneys and be 

 eliminated unchanged. This has been shown actually to occur by 

 Oppenheimer, Ascoli, and others, but probably represents a very 

 unusual state of affairs produced by special experimental conditions. 

 As a rule these substances are disposed of within the body by chemi- 

 cal cleavage or by assimilation. Abderhalden believes that this 

 process depends upon the mobilization of "protective ferments," a 

 term which he borrows from Heilner, 2 and suggests the possibility 



1 Abderhalden. "Schiitzfermente des tierischen Organismus," Springer, 

 Berlin, 1912. 



2 Heilner. Cited from Abderhalden Zeitschr. f. BioL, Vol. 50, 1907. 



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