CHAPTER XX 



SERUM ENZYMES; LEUCOCYTIC ENZYMES; ABDER- 

 HALDEN REACTION; PHYSICAL PRINCIPLES IN 

 SERUM REACTION; MEIOSTAGMIN AND EPIPHA- 

 NIN REACTIONS; COLLOIDAL GOLD REACTION 



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 digestive ferments, is well developed, it is most prob- 

 able that the normal condition of digestion is one in which the 

 foreign substances utilized for nutrition are completely split into 

 their simpler components before they gain entrance to the circulation. 

 Nevertheless, abnormal conditions or accidents, such as gastro-enteric 

 diseases, digestive disturbances, and bacterial infections, may lead to 

 a condition, probably frequent enough in ordinary life, during which 

 such foreign substances may get into the blood stream without pre- 

 vious 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 chemical cleavage or by assimilation. It is more than likely, 

 therefore, as has been emphasized by such workers as Jacoby, Sal- 

 kowski, Wells, and others, that every fluid and cell in the body con- 

 tains enzymes which, by their action upon proteins, fats, and carbo- 

 hydrates, play an important part in the metabolism of the body. 

 It has been known for a long time that the organs of animals re- 

 moved from the body will undergo self-digestion by a process spoken 

 of as autolysis. The action of bacteria as causing such autolysis can 

 be excluded by covering organ emulsions with toluol, chloroform, 

 and some other substances which have the peculiar property of pre- 

 venting the growth of bacteria without in any way interfering with 

 the action of enzymes. Thus, any organ of the body so treated will 

 show rapid changes consisting in the splitting of its own proteins, 



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