1913.] 



Plienomena of" Clot " Formations. 



471 



1 cc. caseinogenate solution — 



+ 0"1 cc. N CaCl 2 solution + 0"9 cc. water Immediate precipitate. 



„ „ +07 „ + 0"2 cc. serum Almost immediate pre- 



cipitate. 



„ „ +0'5 „ + 0'4 ,, Precipitate nearly com- 



plete. 



„ „ +0 - 3 „ + - 6 „ Precipitate incomplete. 



„ „ + 0"1 „ + 0'8 „ No precipitate.* 



4-0-Q * 



In the cases where no precipitate was formed in the cold (indicated by an 

 asterisk, *), it came on warming gently (in the hand), but disappeared again 

 on cooling. A reversible reaction apparently takes place. If, however, 

 rennet is added, the precipitate is rendered permanent. The same phenomena 

 were observed in a further series of similar experiments, iu which, in one case, 

 a 5-per-cent. solution of Witte's peptone, and, in another case, 10-per-cent. 

 solution of glycine, were employed instead of milk serum. 



A further series of experiments was also carried out, in which only half 

 the concentration of calcium salt was present, and the results are as 

 follows : — 



1 cc. caseinogenate solution — 



+ 0"1 cc N/2 CaClo solution + - 9 cc water Immediate precipitate. 



„ „ + 0'7 „ + 0'2 cc serum Turbidity, precipitate 



on warming which 

 is rendered jDerma- 

 nent by rennet. 



ji » +0'5 + 0'4 „ „ 



., „ + 0'3 „ +0"6 „ Precipitate only on 



warming + rennet. 



„ „ + 0'1 „ +0 - 8 „ No precipitate. 



„ „ +0 9 „ No precipitate even on 



warming and when 

 rennet is present. 



Similar results were obtained in experiments in the presence of Witte's 

 peptone and glycine. It will be seen from the above tables that the 

 conditions necessary for the production of a permanent precipitate are some- 

 what complex, and depend on the -relative quantities of inhibitory substances 

 and calcium salt present. They require investigation in greater detail. 

 "Whatever interpretation may be given to the particular action, it will be 

 seen that the ferment can produce an aggregation in a system where it is 

 otherwise inhibited by the presence of simple non-colloidal substances, 

 although, perhaps, the interpretation of its action is not as simple as that 

 suggested in the introduction of this paper. This point will, however, 

 receive attention later, in the discussion of the mechanism of clot formation. 



