416 CHARLES R. STOCKARD AND E. M. VICARI 



the thyroid, is, of course, very small, and differences in rela- 

 tive pituitary sizes are not nearly so conspicuous as thyroid 

 differences. This may be seen by comparing the wide range 

 in thyroid size of the dachshund-Boston terrier groups in 

 text-figure 7!) with the uniformity of pituitary records for 

 the same groups in text-figure 82. A detailed comparison of 

 the relative positions of the individual animals of the F 2 

 series, as indicated below the bars in these two figures, brings 

 out the fact that there is no relation, either direct or inverse, 

 between the proportional sizes of thyroid and the propor- 

 tional amounts of pituitary material. In other words, a rela- 

 tively large amount of thyroid tissue is not regularly asso- 

 ciated with either a high amount or a low amount of pituitary. 

 Within wide limits, the gross quantity of these endocrinic 

 materials seems to be of little functional significance. 



A large number of investigators have recorded the weights 

 of human pituitaries from both normal and diseased cases. 

 The more important of these were conveniently tabulated in 

 a recent study by Rasmussen ( '38) and show, in the first 

 place, that the human pituitary varies widely in size, ranging 

 in adults from an approximate low weight of 200 milligrams 

 up to a high of about 1300 milligrams. Rasmussen calls 

 attention to the fact that some of the weight differences 

 are undoubtedly due to the manner in which the pituitaries 

 were cut from the brain or the infundibular stalk, as well as 

 1<> the varying degrees of thoroughness with which the cap- 

 sules were dissected off before weighing. In Rasmussen's 

 own extensive series of human pituitaries, from 111 adult 

 men and ninety-three women, in which both the capsule and 

 infundibular stalk were completely removed, the male pitui- 

 taries ranged in weight from 358 to 788 milligrams and the 

 female from 448 to 971 milligrams. The human female pi- 

 tuitary is distinctly larger than the male, Rasmussen's mean 

 for the sexes being 618 milligrams for women and 526 milli- 

 grams for men. This difference is in accord with all other 

 such investigations, and is of considerable significance. It is 

 due entirely to the Larger pars distalis in the female; the 



