The effect of the removal of the complete cervical sympathetic nervous system, of both superior and of both inferior cervical ganglia, and of a small portion of the cervical sympathetic nerve in the rabbit was studied in relation to the character of a malignant disease induced by a transplantable neoplasm.
It was found that the general character of the disease which developed in the operated groups of animals was more severe than that of a similar sized control group. Comparisons of the mortality rate in the several groups, of the animal inddence of metastases, the number of metastatic foci, and the distribution of these secondary growths all showed this to be the case. There appeared, furthermore, to be differences in malignancy among the operated groups themselves. The most severe disease occurred in the group in which a portion of the sympathetic nerve only was removed (sympathotomy); that in the complete sympathectomy and superior sympathectomy groups was slightly less malignant; and that in the inferior group was much less so.
These results have been interpreted as due to a less effective animal resistance, the mechanism of which has been interfered with in some way by the interference with the sympathetic nerves. The reasons for the difference in malignancy exhibited by the several operated groups are undetermined. A tentative explanation is suggested upon the basis of coordinating, favorable or deleterious functions subserved by the cervical sympathetic nervous system.