A method is described for studying peritoneal cosinophilia quantitatively in guinea pigs. With repeated lavaging of the peritoneal cavity, the total number of eosinophils accumulating locally each day can be precisely measured. This procedure can be repeated indefinitely in individual animals.
Peritoneal eosinophilia was induced by prolonged series of weekly intraperitoneal injections of horse serum, Limulus hemocyanin or human serum albumin. The response was evident during the first three days following reinjection of foreign protein and ceased by the fourth to the twelfth day. The response was specific, occurring only after reinjection of the same protein used to prepare the animals. With continued injections, the magnitude of the eosinophil response became greater. While the total cell values attained varied considerably from animal to animal, the relative responsiveness of an individual guinea pig remained fairly consistent for months.
In the bone marrow, an increased concentration of eosinophils was found in guinea pigs in which peritoneal eosinophilia could be elicited.
In the blood stream, the reinjection of horse serum resulted in a biphasic response: there was an increase in the concentration of eosinophils during the first 12 hours and again at various times during the next seven days.
Peritoneal exudates were obtained frequently in which as many as 40 per cent of the cells were eosinophils; such exudates commonly contained as many as 50 million eosinophils.