The Monocytic Reaction in Neoplasia of the Rabbit.

Abstract

A study has been made of the cells of the circulating blood of normal rabbits and of rabbits inoculated with various disease-producing agents 1 , 2 including a transplantable malignant neoplasm 3 believed to be of epithelial origin. The results concerning the monocytes in this condition are referred to in the present report.

A variable number of blood counts were taken preceding inoculation and thereafter for 2 months, at which time the experiments were arbitrarily terminated by killing all surviving animals. For the most part, the blood was examined at weekly intervals; a differential white cell count with the supravital technic (vital neutral red) was made at each examination. Six experiments comprising 47 rabbits have been carried out from October, 1927, to March, 1929. In each experiment, a suspension of fresh tumor tissue in normal saline was injected in one testicle of young adult male animals. The course of the disease was followed clinically and the autopsy findings furnished further information concerning the extent and degree of the disease process.

The blood observations have been analyzed with respect to the clinical and postmortem findings and in the present instance, are considered from a group standpoint. The following classification of animals has been employed: deaths, probable deaths, and recoveries. The first group includes examples of widespread metastatic involvement; the probable deaths comprise those rabbits in which the site and character of the growth found at autopsy 2 months after inoculation were such as to make it appear probable that death would ultimately have resulted from tumor; the recoveries include those animals in which healing of tumor had occurred and in addition, a few instances of slight residual tumor, the nature or location of which was considered as not constituting a probable cause of death.