STUDIES BASED ON A MALIGNANT TUMOR OF THE RABBIT

The results obtained by intratesticular inoculation of a malignant tumor of the rabbit are presented in the form of a general summary covering the phenomena of growth and spontaneous regression of the tumor and the clinical evidence of disease in tumor animals. Under ordinary circumstances, growth is obtained by this method of inoculation in practically all animals, and the majority of them show metastases. The ultimate fate of tumor animals is variable. Spontaneous regression is of frequent occurrence, and apparent recovery may take place even after extensive metastases have developed. More often, the disease terminates fatally. The course of the disease may be fulminating in character with death occurring 6 to 7 weeks after inoculation, or it may be prolonged over a period of more than 6 months, but death usually occurs between 7 weeks and 3 months after inoculation. The symptomatology varies with the course of tumor growth but is in general that of a debilitating disease of an acute or chronic character in which the picture is frequently complicated by symptoms referable to mechanical causes or to one or more of the glands of internal secretion. The most prominent of these are due to the presence of metastases in the suprarenals or pituitary body, in which case symptoms of Addison's disease or diseases of the pituitary may be superimposed upon those attributable to the presence of extensive tumor growths. In the absence of such growths, however, the symptoms of suprarenal or pituitary involvement may dominate the picture.