BLOOD SUPPLY OF THE PITUITARY BODY 139 



sis.- Herring was the first to show that the anterior and posterior 

 lobes possess independent blood suppHes, the former coming 

 down through the stalk, the latter entering the posterior lobe 

 from behind. No comment was made, however, on the origin of 

 these vessels. Substantially the same results were obtained a few 

 years ago by Dr. G. J. Heuer in unpublished studies carried on 

 independently in this laboratory. 



Our observations, as will be seen, entirely confirm the views of 

 Herring upon the general plan of the gland's internal circulation, 

 but especial emphasis is placed upon the grosser circulation, in 

 view of its experimental and surgical importance. 



MATERIAL AND METHODS 



Immediately after death the animals were injected head ward 

 through both common carotid arteries, during which process 

 the principal veins of the neck were ligated or a tourniquet applied 

 to obstruct the venous return of the injection mass. Of the numer- 

 ous colored masses, we have derived the best results from a 10 per 

 cent gelatin mass with carmine or vermillion for the veins and 

 capillaries, and Prussian blue or ultramarine for the arteries. 

 Satisfactory injections may be obtained by following a primary 

 carmine injection by one of Prussian blue, a double injection 

 being obtained — the veins red and the arteries blue — since the 

 larger granules of the blue mass are unable to pass through the 

 capillaries. 



Carmine gelatin, although the best general injection mass, 

 is a very capricious substance, requiring careful preparation, 

 for if too alkaline it diffuses through the vessel wall, or if too acid 

 it precipitates. We are indebted to Dr. M. J. Burrows of the 

 Rockefeller Institute for the benefit of his experience in the rather 

 elaborate preparation of this mass. 



2 Herring, P. T. The histological appearances of the mammalian pituitary body. 

 Quarterly J. Exper. Physiol., 1908, i. p. 154. In this article Herring gives an 

 excellent photograph (fig. 16, p. ]54) of the injected feline hypophysis, which 

 shows unusually well the relatively greater vascularity of the anterior lobe. This 

 condition is rarely and with difficulty brought out by a simple arterial injection, 

 which usually shows little more than in our fig. 4. 



