64 The Veins of the Adrenal 
similar size occurring in other organs. The veins, however, present 
distinct and remarkable peculiarities which it is the purpose of the 
present paper to describe. 
Methods and Material—The tissue used for this study has included 
specimens of the adrenal from twenty-one human adults, together with the 
casual examination of fetal adrenals of the pig and of man. The 
adrenals of other mammals, e. g., monkey, dog, cat, rabbit, and guinea- 
pig, have also been more or less carefully studied. 
These tissues have been fixed and hardened with many reagents, among 
which are Zenker’s solution, formol, Miiller-formol, alcohol, corrosive 
acetic mixture, Tellyesniczky’s fluid, and Flenming’s solution. The 
stains used were hematein by various methods, acid hematein, iron 
hematein, etc., and for counter staims eosin, orange, Van Gieson’s picro- 
fuchsin, Weigert’s elastic tissue stain, Mann’s methyl blue-eosin mixture, 
Congo-red, and Ehrlich’s triacid mixture. A combination of Mann’s 
hematein, Weigert’s elastic tissue stain and Van Gieson’s picro-fuchsin, 
gave the best results for the differentiation of the muscular and con- 
nective tissues. This method was applied as follows, and may be used 
after any of the above fixatives. 
1. Stain 10-12 minutes in Mann’s hematein or in Bohmer’s hema- 
toxylin, until somewhat overstained. 2. Wash well in water. 3. Stain 
10-20 minutes in recently prepared resorcin-fuchsin solution after the 
method of Weigert (9). 4. Wash in water. 5. Stain 1-3 minutes in 
the freshly prepared picrie acid-acid fuchsin solution of Van Gieson 
(10). 6. Wash and dehydrate in 95 per cent, or in absolute alcohol. 
7. Clear, and mount. 
Types of Adrenal Veins.—The efferent veins of the adrenals arise in 
the medulla of the organ by the union of the broad capillaries of the 
medulla and the adjacent zone of the cortex. These capillaries form 
broad thin-walled vessels which have been described by Minot (6) as 
sinusoids. They converge toward the middle of the medulla, where they 
pass into somewhat larger vessels, which, for convenience, may be termed 
small central veins. These veins tend toward the hilum, are relatively 
short, and by union with one another soon form thicker-walled vessels 
which may be described as large central veins. These large veins pass 
toward the hilum, near which,they unite to form a large efferent vessel, 
the suprarenal vein. This last vein makes its exit from the hilum of the 
organ and enters either the vena cava inferior, as is the rule on the right 
side, or the renal vein, as frequently occurs on the left.” 
From this brief review of the course of these vessels it will be seen that 
four distinct venous types have been enumerated, and it is the purpose 
