216 ANTI-ENZYMES 



the case of antirennin (" Antilab."); lie obtained it in a similar 

 fashion to an antitoxin by injection of increasing doses of rennet 

 solution, and found that both the serum and the milk of the in- 

 jected animal possessed in a high degree the power of preventing 

 the coagulation of caseinogen by the action of rennin. Anti- 

 bodies have since been obtained to pepsin, trypsin, fibrin ferment, 

 laccase, urease, and tyrosinase. 



It has been urged that this reaction of the tissue cells to fer- 

 ments shows that the toxins of disease and various poisons of 

 animal and vegetable source act similarly to enzymes, and produce 

 their effect in a similar catalytic fashion, until their action is para- 

 lysed by the production by the tissue cells of the appropriate 

 antitoxin. Although there is no doubt whatever as to the pro- 

 duction of the antitoxins and of the anti- enzymes, we do not yet 

 know enough regarding the processes to generalise as to the action 

 of toxins and enzymes being the same, and the wide generality 

 in the reaction of the cells in producing an antibody to almost 

 anything which is presented to them, as has now been demonstrated 

 for hundreds of bodies, indicates that the formation of the anti- 

 body is a general act of protection of the tissue cells and not one 

 specially directed against catalysts or enzymes only. 



Weiland states that antitrypsin exists ready formed under 

 normal conditions in the cells of intestinal worms, and in the cells 

 of the intestinal mucosa, as shown by the fact that cell- free extracts 

 of these protect fibrin against tryptic digestion. The proteins 

 of the serum in unaltered form show a great resistance against 

 trypsin, which is lost when they have been chemically altered 

 by coagulation, or the action of chemical reagents, and this re- 

 sistance has been ascribed to the presence of an antitrypsin. 



Since the discovery of enterokinase the view has been advanced 

 by Dastre and by Delezenne that the effect of preventing the 

 action of the trypsin is not due to an antitrypsin but to an 

 antikinase, which prevents or opposes the activation of the 

 trypsin by the enterokinase. 



ZYMO-EXCITATORS OR KINASES. 



The various enzymes are not at first produced in an active 

 form in the cells of the glands which secrete them, but as inactive 

 substances called zymogens or proferments. This was first shown 



