PLATELETS— VILLALOBOS, ADELSON and RILEY 197 



carried to the low levels reached in dogs, both patients showed the preliminary 

 decreases found at comparable temperatures in the animals. 



Dr. Jonathan Rhoads: If the liver and spleen do not completely account for se- 

 questration of platelets and white cells, could the gut be a reservoir? 



Dr. Adelson: We did not study this. I would like to point out that coagulation- 

 time studies in glass tubes are less accurate than when carried out in silicone tubes. 



Dr. James A. Hcliiiszvorth: The hematologic aspects of hypothermia attracted 

 our attention because of the development of an hemorrhagic diathesis in dogs sur- 

 viving cooling by immersion in ice water in our laboratory. A large proportion of 

 these animals had profuse bleeding into the intestinal tract and died in shock within 

 18 hours after chilling. Our findings in reference to the changes in the platelet 

 count confirm those of Crosby and Adelson. The average reduction in platelet count 

 was 86% in dogs cooled by this method to a body temperature of approximately 

 25° C. The same measurements were carried out in a small group of monkeys 

 cooled by the same method and to the same extent, and in these animals there was 

 the same marked thrombocytopenic effect. There are two additional comments 

 which are of some interest. The first is that, in dogs cooled by the same method 

 and to the same temperature, the thrombocytopenic effect was much less if autonomic 

 blockade had been established by xArfonad. Indeed, in some of these "blocked" ani- 

 mals the platelet count remained unchanged. The second is that dogs cooled by 

 means of a simple extracorporeal circuit do not show the same fall in platelet count. 

 In this group of animals with blood flowing from femoral artery to femoral vein 

 through a simple plastic tube the platelet count has, on many occasions, remained 

 normal even though the changes in body temperature were of the same degree men- 

 tioned before. 



Dr. J. Adams-Ray: We have made some observations that seem to fit with the 

 sequestration of blood in the liver in hypothermia as indicated by Dr. Adelson. 

 The method used for measuring variations of the liver volume is a roentgenstereo- 

 photogrammetrical one.^ Small silver pellets are placed on the liver so that they 

 enclose a polyhedron. With two X-ray tubes with known distance in relation to film 

 these will be photographed at intervals during the experiment. Each pellet will then 

 be reproduced at two places. Measuring the distance between the two images of 

 each pellet, and knowing the distance between the X-ray tubes and the distance 

 between the tubes and film, we can locate each pellet in an orthogonal-coordinate 

 system. The volume of the polyhedron enclosed by the pellets can then be computed 

 and the mean error of the volume determinations is somewhat below 1 per cent of 

 the total volume measured. The calculations are easily made by using a punch-card 

 system in a calculating machine. 



In hypothermia we found a slight increase in liver volume,- observable even at 

 26° to 28° C. rectal temperature. This was in contrast with the considerable de- 

 crease of liver volume that my associate, Dr. Hagberg, found in hemorrhagic 

 shock, which would give anoxia, possibly interfering inter alia with the bacterial 

 defence mechanisms described by Jacob Fine. When Dr. Hagberg induced hypo- 

 thermia during such experiments the decrease of liver volume was inhibited. His 

 experiments are not yet concluded but indicate a protecting effect of hypothermia 



