The Action of " Peptone " on Blood and Immunity thereto. 375 



the delay in completion was 40 minutes 40 seconds. The addition of 

 corresponding amounts of - 9 per cent, sodium chloride to shed blood did 

 not produce any appreciable variation in the coagulation time. A com- 

 parison of Experiments Nos. 8 and 9 with No. 6 shows that the retarding 

 effect of a concentration of 1 per cent, of " peptone " dissolved in distilled 

 water was actually less than that of 0'325 per cent, dissolved in normal saline. 

 This result falls into line with the observation of Howell (38) that while 

 dilution of peptone plasma with water induces coagulation, dilution with 

 - 9 per cent, sodium chloride has no such effect. 



In the next three observations, endeavours were made, with success, to 

 prolong the anticoagulant action of small amounts of " peptone " in vitro by 

 reducing the disturbance to the colloidal complexes of the plasma incidental 

 to the shedding of blood. 





Control 

 blood on 

 glass. 



Control 

 blood on 

 paraffin. 



0-3 p.c. 

 peptone 

 blood on 

 paraffin. 



0-3 p.c. 

 peptone 

 blood on 

 paraffin. 



0-6 p.c. 

 peptone 

 blood on 

 paraffin. 





/ // 



/ // 



/ // 



/ // 



/ // 



Time of adding " peptone "... 























Time of "commencement" 



8 55 



24 20 



32 40 



34 45 



45 20 



of clotting 













Time of " completion " of 



12 15 



27 40 



107 30 



136 



135 



clotting 



















11 



12 



13 



Notes. 



In Nos. 12 and 13, after 171 minutes there was still some nnclotted blood. 



Many experiments of this nature haTe been carried out in this connection. Only one is given. 



Experiments. 



In these experiments, blood from the carotid through a paraffined cannula 

 was received into paraffined vessels, as free from dust as possible. With 

 - 3 per cent, of " peptone " (dissolved in - 9 per cent, sodium chloride) in the 

 blood, again mixed in vitro, the delays in the commencement of clotting 

 exceeded 23 minutes, as compared with the coagulation time on glass, a 

 result which was not more marked than was obtained with - 325 per cent, 

 of " peptone " dissolved in 9 per cent, sodium chloride, mixed in an 

 uncoated glass vessel. The distinctive difference between the results on 

 glass and paraffined vessels is that, in the former, coagulation, once it has 

 commenced, proceeds rapidly, and is completed in a few minutes, while in 

 the latter it is a relatively slow process, occupying from 1 to 2 hours. In 

 some cases, indeed, the first formed small clots are exhibiting syneresis 

 (conti'action), while other clots are still forming. Thus, in the less 



