RELATIONS OF ANTERIOR AND POSTERIOR PITUITARY. 209 



many vessels, arterial and venous. This lobe unlike its mate, 

 in which are found neuroglia, nerve-cells and epithelial-cell 

 tubules that contain a colloidal material is subdivided into 

 numerous cavities, or vesicles, that vary in size and the walls 

 of which are lined with acini, made up of epithelial cells. Some 

 of these acini, especially those near the posterior lobe, also 

 contain a colloidal substance. The glandular elements are sur- 

 rounded by a close net-work of lymphatics and capillaries, 

 which, as we have seen, may become the seat, not only of in- 

 tense engorgement, but also of haemorrhage. The anterior 

 lobe, on the whole, recalls the thyroid in histological structure, 

 and several investigators Rogowitsch, Gley, Stieda, and others 

 have observed hypertrophy of its elements when the thyroid 

 was removed. In a large proportion of the cases of acromegaly 

 it is also this lobe that exhibits the morbid changes: an analogy 

 which suggests that its secretion might also be similar to that 

 of the thyroid. Is this the case? 



If the secretion of the anterior lobe were similar to that of 

 the thyroid, there should also be considerable analogy between 

 the products of these organs and the secretion of the thymus, 

 since, as we have suggested, the pituitary appears to be, in this 

 particular at least, one of the successors of the latter. This 

 involves the presence, in all three of the organs, of the chem- 

 ical bodies upon which the hardness of the osseous frame-work 

 depends, since the preponderating phenomenon of disease of 

 the anterior lobe of the pituitary is bony overgrowth, while 

 removal of the thymus, as shown experimentally, is followed by 

 softness and bending of the bones. The administration of 

 thyroid extract in cretinism, on the other hand, is followed by 

 overgrowth, but with coincident softness of the bones: a feat- 

 ure which in itself seems to negate the presence of phosphorus 

 in the thyroid secretion. 



R. HutchinsonV 5 analyses of the thyroidal colloid have 

 shown that the proportion of phosphorus was 0.4 per cent., all 

 contained in a non-proteid part separated from the colloidal 

 substance by the action of boiling acids or the gastric juice. 

 Baumann's iodothyrin owes its activity to this non-proteid con- 



R. Hutchinson: Journal of Physiology, Dec. 3, 1896. 



