PLATI'XETS— VILLALOBOS, ADKLSOX and RILEY 



195 



I 



«0 



10- 

 9- 

 8 



7 

 6 

 5 





40 

 30 

 20 



15 



150,000 



100,000 



50,000 







13,000 

 8,000 

 3,000 



35 

 30 

 25 

 20 

 15 



+ + + 



+ + 



2 3 



Time in Hours 



Prothrombin time 

 I n plosmo 

 12 dogs 



Prothrombin time 

 in serum 

 6 dogs 



Piotelet count 

 1 1 dogs 



+ 4- 



Clot ret roction 



1 1 dogs 

 LeuKocyte count 



Temperoture 



Fig. 2. — Prothrombin time in plasma, prothrombin time in serum platelets, clot retraction, 



leukocyte count. 



Coagulation times in glass were not significantly altered by cooling. Coagulation 

 times in silicone tubes were altered as others have shown. This difference is no 

 doubt due to the reduction in the platelets which occur with cooling. 



There was a five- fold increase in the bleeding time as a result of cooling. Five of 

 the 12 dogs tested had a seven-fold increase at reduced temperatures. One dog had 

 a bleeding time of 17 minutes, which falls well beyond the normal range. This 

 process is completely reversible with rewarming. 



The hemoglobin and hematocrit invariably rise with cooling. 



The prothrombin time in plasma by the one stage method was not greatly altered 

 by cooling in our series. However, the prothrombin time in serum is significantly 

 decreased. This being a measure of residual prothromljin, it is quite possible that 

 this decrease could be due to the i)latelet drop which occurs. 



The platelet count drops to a very low level with cooling. In some of otir animals 



