Increase of Blood Platelets in Rabbits by a Specific Bacterial Infection.

Abstract

In the course of an experiment on rabbits in which the effect of splenectomy upon blood platelets was being studied, a peculiar caseous necrosis about the site of operation was encountered in one of the animals. This was found to be due to an infection with a motile, Gram-negative bacillus. From the studies made on the bacillus so far, it can with certainty be excluded from the Salmonella group; moreover it cannot be identified with any of the human pathogenes. Further studies are in progress and will be reported upon later. Because of an unusual increase in number of blood platelets in the infected animal, six healthy rabbits were inoculated with the cultured micro-organisms and the effect upon platelets observed.

Results. The accompanying Table I shows the change in number of platelets and leucocytes in these six animals and indicates the pathological changes in the four which were examined post mortem. The greatest increase in platelets in any one animal was 3.4 times its normal, while the greatest so far obtained with ultra-violet light is 2.3 times. The greatest increase in three splenectomized rabbits was 2.5 times the normal.

The maximum leucocyte number found in the uncomplicated cases was 23,000, which was observed in Rabbit 27. Of this number about 65 per cent were small lymphocytes, whereas in Rabbit 26, which developed an accidental pyogenic infection, over 70 per cent of the 35,000 leucocytes were polymorphonuclears.