28 CAREY P. McCORD 



Careful observations were made of the growth of the experimental 

 animals. Skiagraphs were taken at various periods, but there was no evi- 

 dence of either superior or inferior somatic development or adiposity, save 

 perhaps in a single instance. In this animal there was slight increase 

 in weight for a brief period, about one year after the operation. This 

 gain, however, might be attributed to overfeeding. There was nothing in 

 the behavior of the experimental animals to suggest mental precocity. 



Dandy observed nothing to support the view that the pineal gland in- 

 hibits the sexual functions, and that its removal is followed by excessive 

 sexual development. Two bitches lived for one year following the removal 

 of the pineal; both were in rut ten months after the operation, or when 

 about one year old. In neither animal did pregnancy result, and in 

 neither was any abnormality observed in the generative organs. 



The experimental young male puppies, observed for periods of from 

 three to eight months, contrasted with other members of the same litter, 

 gave no evidence of sexual precocity or retardation. 



Dandy's experiments led him to the final conclusion that, so far as his 

 work went to show, pineal extirpation gives rise to no sexual precocity, 

 indolence, adiposity, nor emaciation and no somatic or mental precocity or 

 retardation, ^o evidence was found that the pineal has an active endocrin 

 function in either young or adult dogs. The organ is not essential to life 

 and seems to have no influence upon the animal's well being. 



From the literature as a whole, no final conclusions can be drawn. As 

 a general principle in biologic experimentation, negative results in one 

 species cannot be regarded as disproving positive results in another. They 

 do, however, if performed with adequate technic, establish a sufficient de- 

 gree of antecedent probability of error as to demand further studies. It 

 is within tho realms of possibility, that in some species the pineal retains a 

 degree of functional capacity which has been lost in others. It is possible 

 that in the dog the pineal function has been completely taken over by 

 other organs. In such case, only negative results could be expected. It 

 is to be hoped that further studies may soon be made in a variety of ani- 

 mals, and that the question may be settled beyond peradventure, as to 

 whether pineal deficiency results in any characteristic changes in growth 

 or development, and especially in the sexual sphere. 



Ill 



Chemistry of the Pineal Gland 



Assaying Pineal Materials. Because of the relative unimportance of 

 the pineal gland in the endocrin congeries, but meager attention has been 

 devoted to the development of methods for the quantitative assay of pineal 



