Differential Cell Count of the Peritoneal Fluid from the Normal Guinea Pig.

In carrying out studies on the cellular reactions provoked in the guinea pigs’ peritoneal cavity by the injection of tubercle bacilli, differential cell counts were made upon a series of peritoneal fluids previous to the inoculations. This has furnished such a large number of counts upon the normal peritoneal fluid that it has seemed worth while to collect and report the figures, particularly since there is no general uniformity in the results published by other writers,1, 2, 3, 4, 5, 6Peritoneal fluids from 237 apparently healthy guinea pigs have been examined, and as no effort was made to select a particular type of animal, this group probably represents a fair average of any laboratory stock. The observations have been carried on over a period of several years during both winter and summer months. Therefore any effects attributable to seasonal or dietary conditions may be assumed to have been comprehended. The majority of the animals were purchased from 4 different sources; a few were raised in the laboratory. They were of both sexes, of many colors, and they varied in age from a few days to several years.Without previous injection of salt solution or other liquid, samples of peritoneal fluid were withdrawn through sterile capillary pipettes and supravital preparations with neutral red or neutral red-Janus green were made. Differential cell counts were done on 200 living cells after 5 or 10 minutes’ incubation in the warm box. At first as many as 1,000 cells were counted, but this was found to be unnecessary as the distribution of cells in the fluid from the normal peritoneum is very uniform if the preparations are properly made. The serosal cells were not tabulated as their occurrence is probably more or less accidental.