Method for Testing Ferments and Anti-ferments. 63 



0.47 per cent. " 2 " 58 " 



0.46 per cent. " 2 " 58 " 



0.45 per cent. " 3 " 



0.44 per cent. " 3 " 



0.43 per cent. " 3 " 02 " 



0.42 per cent. " 3 " 02 " 



0.41 per cent. " 3 " 04 " 



0.4 percent. " 3 " 04 " 



The accuracy with which the antitryptic value of serum can 

 be determined, is illustrated by the following series of tests : 



I c.c. I per cent, serum -f- I c.c. 0.2 per cent, trypsin, I min. 57 sec. 



1 c.c. 2 per cent. 

 I c.c. 1.5 per cent. 

 I c.c. 3 per cent. 

 I c.c. 2 per cent. 

 1 c.c. 4 per cent. 

 I c.c. 2.5 per cent. 

 I c.c. S per cent. 



-f- I c.c. 0.4 per cent. " I " 58 



-f- I c.c. 0.2 per cent. " 2 min. 



-f- 1 c.c. 0.4 per cent. " 2 " 



-j- 1 c.c. 0.2 per cent. " 2 " 2 



+ 1 c.c. 0.4 per cent. " 2 " 2 



-f- 1 c.c. 0.2 per cent. " 2 " 4 



-f- 1 c.c. 0.4 per cent. " 2 " 5 



Thus, it will be seen that the method permits of a very accurate 

 estimation of the action of ferment at any given moment, and of 

 the restraining action of anti-ferment, which can be progressively 

 followed over considerable periods of time. It necessitates the use 

 of only one dilution, instead of a series, as in previous methods. 

 It determines the end-point exactly, instead of approximately. It 

 determines variations in the media by means of the use of controls 

 in each experiment, which is not possible by the methods now in 

 use. 



In testing human sera with a gelatin of an original viscosity 

 time of four minutes, a trypsin of 0.5 per cent, strength and sera 

 of 2 per cent, dilution, the range of inhibition covers approxi- 

 mately 60 seconds, so that the values of sera may be far more 

 sharply differentiated than is possible with a series of five dilutions, 

 as in the methods hitherto used. 



We shall not give the details of the tests hitherto made, which 

 embrace about two hundred sera of various conditions of disease. 

 It is, however, worthy of emphasis, we believe, that the so-called 

 anti-tryptic action of human sera manifests altogether different 

 relative values when tested against the proteolytic ferment present 

 in a glycerin extract of cancers as compared with the commercial 

 trypsin derived from animals. 



