Antitrypsin of the Serum. 



143 



as a given serum may show an inhibition of only five per cent, of 

 the total digestion against one organ enzyme, and as much as 95 

 per cent, against another. With a second serum, again, these 

 relations are found reversed. It seems impossible to interpret 

 these results otherwise than as indicative of the existence of a 

 variety of ferments, each one more or less characteristic of the 

 organ from which it is derived. This multiplicity of proteoses 

 has recently been suggested by Vernon as the probable explanation 

 of certain differences shown in comparative digestion experiments 

 with the pressed juices obtained from the various organs. At the 

 same time, it seems necessary to assume the existence in the serum 

 of a corresponding variety of anti-ferments. 1 It is, therefore, evi- 

 dent that it is impossible to speak of the "anti-tryptic" activity 

 of serum, inasmuch as this term comprises a heterogenous set of 

 functions. An observation which will prove to be of interest, if 

 confirmed by a wider series of experiments, is the fact that sera 

 derived from cases of cancer have hitherto shown a characteristic 

 mode of reaction. Their inhibitory activity against commercial 

 trypsin has in general been very high, as previously determined 

 by many German observers, by the casein method of Gross; in 

 some cases it has been normal or average; in others, very low. 

 In no case, however, has the inhibition exercised by any cancer 

 serum against the "tryptic" ferment derived from a cancer notably 

 exceeded its inhibition of trypsin; in almost all cases it has fallen 

 enormously below the latter. In the normal control cases, these 

 relations have hitherto been exactly reversed. An explanation for 

 these facts the authors do not consider possible as yet. At all 

 events, the viscosimeter seems to afford a simpler method than 

 any yet devised to determine these complex relations of the serum. 



'Whether the inhibitory activity of the serum is in reality attributable to true 

 anti-ferments cannot be discussed here, but to the authors this seems the only likely 

 explanation of certain conditions, in spite of the fact that Hedin was able to reproduce 

 some of the phenomena of inhibition by the use of charcoal. 



