834- 



SUPRA-RENAL CAPSULES. 



object is fulfilled by this united condition of 

 the nerve fibres. 



In Birds, the structure of these vascular 

 glands is even more uniform than in the pre- 

 ceding classes. No separation into cortical 

 and medullary substance appears to occur in 

 any bird. A single observation of Meckel's 

 states that in the Cassowary the two kinds of 

 substance are to be distinguished ; but this 

 statement is contradicted by the numerous 

 negative observations of Cnvier, Ecker, Bar- 

 deleben, and Nagel, on all the animals of this 

 class which they have examined, and hence 

 it requires a confirmation. The supra-renal 

 capsules of birds appear of a darkish or clearer 

 yellow colour, which, by the varying amount 

 of blood they contain, tends more or less 

 towards red. They are also enclosed in a 

 sheath of areolar tissue, and exhibit a basis 

 which consists of fibrous tissue and blood- 

 vessels. In this matrix the gland-vesicles 

 lie imbedded throughout the whole thickness 

 of the organ, and they are devoid of any 

 regular arrangement. They are of roundish, 

 oval, pear-shaped, or irregular form. Their 

 size varies from 44* to 56-1000ths of a line, 

 and in the Falco tinnunculus some of them 

 even attain the size of 22-100ths of a line. 

 Their membrana propria is very delicate. The 

 structure here specified may be best wit- 

 nessed in the supra-renal capsules of large 

 birds ; nevertheless, with some care, we may 

 succeed in recognising the gland-vesicles in 

 the smaller members of the class, as, for 

 instance, in the Pigeon. 



The contents of their gland-vesicles closely 

 resemble those of the Mammalia. There are 

 the same fine pulverulent molecules of a pro- 

 tein compound ; and fatty granules, which are 

 usually in very large quantity, have a yel- 

 lowish colour, and give rise to the tint pos- 

 sessed by the whole organ. Not unfrequently 

 larger yellow drops of fat are visible. Besides 

 these, we come upon the granular nuclei pre- 

 viously mentioned, possessing a size of 22 to 

 31-10,000ths of a line. Some of these nuclei 

 are also enveloped in a fine granular mass, 

 and exhibit a transition to cells in the mode 

 which we witnessed in the Mammalia. Not 

 unfrequently the nuclei are completely buried 

 in fatty granules, through which they are only 

 visible as clear spots. In the golden Eagle 

 Ecker remarked complete cells filled with 

 fatty granules ; these were probably caused 

 by the usually finely granular cells becoming 

 gradually filled with fat. In many of the 

 gland-vesicles, on the contrary, the fat is re- 

 markably diminished in its proportion to the 

 finely granular substance ; and it has been 

 conjectured by Ecker, and with great pro- 

 bability, that this difference in the amount of 

 fat depends upon the different stages of deve- 

 lopment of the gland-vesicles. In a very 

 young Pigeon I have found scarcely any fat 

 molecules, a fact which has some connection 

 with this statement. 



The minute anatomy of the supra-renal 

 capsules of the Kept ilia is as yet insuffi- 

 ciently known. 



In the supra-renal capsules of Lacerta agilis, 

 Ecker was with some difficulty able to re- 

 cognise the same condition as that seen in 

 the higher Vertebrata; but the presence of a 

 membrana propria around the gland-vesicles 

 was especially indistinct. He only remarked 

 masses of a darkish substance. These masses 

 consisted of fatty granules of the nuclei al- 

 ready described, and of granulated globules, 

 which contained a nucleus, and possessed a 

 size of 31 to 44~10,000ths of a line. 



In the Adder, the obscurity of the contents 

 uncommonly aggravates the difficulty of ex- 

 amining their lobuluted supra-renal capsules ; 

 but in the foetal Adder of three inches length, 

 Ecker was able to verify the separate gland- 

 vesicles in the usual manner. Here also 

 nuclei were seen ; and, besides these, large 

 pale gland-cells, which could not long resist 

 the action of water. Other cells were com- 

 pletely buried in fatty masses, just as they 

 were seen to be in the carnivorous Mammalia. 



The arrangement of the vessels of the 

 supra-renal capsules is peculiar in the Snakes, 

 inasmuch as the greater part of the blood is 

 not brought to the organ by means of ar- 

 teries, but by veins. In consequence of this, 

 the supra-renal capsules have a kind of portal 

 venous system, such as is possessed by the 

 kidneys of lleptilia and the liver of Verte- 

 brata. The afferent supra-renal veins arise 

 by two branches from the wall of the body, 

 and from the plexus venosus of the vertebral 

 canal ; and after a tolerably long and isolated 

 course they reach the supra-renal capsules. 

 On an average, the right supra-renal capsule 

 receives two or three branches ; but the left, 

 which is wont to be smaller, only one or two. 

 The arterial blood is brought to the supra- 

 renal capsule by one or two vessels which 

 are branches from the aorta. 



Both kinds of vessels ramify in the sub- 

 stance of these organs, so as to form a fine 

 capillary network. The efferent supra-renal 

 veins arise from this network in the form of 

 numerous small trunks. They pass from the 

 right supra-renal capsule immediately into the 

 vena cava posterior; but from that of the left 

 side into the inferior cava, and also into the 

 efferent renal vein. 



In his examinations of the Tcstudo graeca, 

 Ecker found certain bodies, which he regards 

 as the supra-renal capsules of the Chclon'mn 

 reptiles. By microscopic examination, they 

 appear as yellow granules which are grouped 

 together in heaps. Each of these is en- 

 closed in a membrana propria, and thus con- 

 stitutes a gland-vesicle. Their contents are 

 altogether identical with those of the Batra- 

 chia, to which we shall next apply ourselves. 



In the tailless liatraclna, the yellow lobules 

 already described consist of groups of vesicles. 

 Their form varies ; sometimes it is round, 

 sometimes oval, sometimes elongated or irre- 

 gular. The vesicles are always closed, and it 

 is only when they are grouped together that 

 they appear at first sight like blind sacs. 

 Fatty granules constitute the greater part of 

 their contents ; but besides these, the fine 



