THE OCCURRENCE AND TREND OF SPONTANEOUS VARIATIONS IN ORGAN WEIGHTS OF NORMAL RABBITS.

Records of organ weights of normal rabbits covering a period of 3(1/2) years were analyzed with a view to determining first, whether any significant variations of an orderly character could be demonstrated and, second, the general trend of the variations that occurred. It was found that many organs showed decided variations in weight which assumed the form of definite annual cycles. In addition, there was some evidence of a second cycle covering a period of years. These changes were most marked in the case of the endocrine glands (including the testicles), the lymphoid organs, and the liver.