830 



SUPRA-RENAL CAPSULES. 



vertebral arch : this occurs in the genera 

 Cyprinus, Tinea, Pleuronectes, Anarrhichas, 

 Scomber. Or they occupy more the middle 

 of the kidney, as in the Salmo Salar. On the 

 other hand, they are found on its abdominal 

 surface in the Eel and Pike. They lie in this 

 situation very anteriorly, occupying, in the 

 Eel, the place where the two crura of the 

 renal mass unite. In the Pike they are yet 

 more advanced forwards, so that they coaie 

 to lie in the middle point of the length of the 

 body. 



Amongst the cartilaginous fishes, the supra- 

 renal capsules seem in the Squalidoe to be 

 only present as a single mass. This, in the 

 shape of a small ochre-yellow stripe, oc- 

 cupies the dorsal surface of the kidneys. 

 But in the Rays the supra-renal organs form 

 a curved cylinder, which is constricted at two 

 points, and lies on the ureters ; at least 

 Retzins formerly stated this to be its condi- 

 tion. Stannins sometimes found in this genus 

 a similar elongated body behind the kidneys : 

 or, in other instances, four or five small glan- 

 dular corpuscles were present in its place. 

 And the latter observer found that the supra- 

 renal glands of the Sturgeon * consisted of 

 similar corpuscles in much larger number. 



The supra-renal capsules of the cartila- 

 ginous fishes have a yellow colour, and are 

 also plainly lobulated. 



As has' been previously remarked, in the 

 least developed fishes the supra-renal cap- 

 sules have not been discovered, at least not 

 with any certainty, so that their existence 

 must remain a matter of doubt. In the 

 Myxinaid fishes, J. Miillerf found behind the 

 gills, and on each side of the cardia, a clus- 

 tered gland which was devoid of an excretory 

 duct. He interprets it as a supra-renal organ; 

 and regards as analogous to it the white 

 specks with which the trunks of the posterior 

 veins of the body are beset in the Ammo- 

 caetes.J But the minute structure of the 

 glands in question in the Myxinoid fishes, 

 which is also described by Miiller, seems ra- 

 ther to contradict the explanation attempted. 

 And Ecker discovered a gland in the Petro- 

 myzon between the aorta and the great vein 

 of the body, and partly lying in the coat of 

 the latter : but this also had not the struc- 

 ture of a supra-renal capsule. 



II. We next proceed to the minute struc- 

 ture of the supra-renal capsules, concerning 

 which Ecker has given a very good and fun- 

 damental description, so that we shall here in 

 great degree follow him. In Man and all 

 the Mammalia, they exhibit two kinds of sub- 

 stance, which have been designated by the 

 names of cortical and medullary substance. 

 The first is clearer than the latter, being in 

 Man of a yellowish-brown colour ; while the 



* Stannius, Lehrbuch der Vergleichender Ana- 

 tomie der Wirbelthiere, Berlin, 1846, S. 118. 



f Vergleichende Anatomic der Myxinoiden. 

 Schluss. In der Abhandlungen der Academie der 

 Wissenschaften zu Berlin, 1843, S. 118. 



J Rathke, Beitrage zur Gescliiclite der Thicrwelt, 

 4te Abtheilung, S. 99. 



medullary substance possesses a reddish- 

 brown hue. In many instances, the two 

 kinds of substance are little distinguishable 

 by the naked eye, so that the supra-renal 

 capsules exhibit only a simple mass, such as 

 Cuvier has described that of the Elephant to 

 be. Besides this, the amount of the two 

 layers varies very considerably. The cortical 

 substance is of some solidity ; while, on the 

 contrary, the medullary matter is very delicate 

 and flaky. This great delicacy, together with 

 its considerable richness in blood-vessels, 

 makes it very probable, that the medullary 

 substance of the supra-renal capsules is de- 

 composed very quickly after death. And this 

 gives rise to the formation of a cavity, con- 

 taining a brownish-red fluid, which is not un- 

 frequently found in the interior of the human 

 supra-renal capsules. Formerly this cavity 

 was regarded as normal and occurring during 

 life. The name " capsulae atrabilariag " is 

 connected with this notion, since these cavi- 

 ties were described as real by the older ana- 

 tomists. And although decomposition is 

 regarded as the chief agent in the formation 

 of these cavities, yet pathological conditions 

 seem to be by no means without their influence 

 towards them. Thus Rayer tells us the de- 

 velopment of cavities may occur in conse- 

 quence of rupture of the venous coats, and 

 the effusion of blood in the medullary sub- 

 stance.* Nagel also remarks concerning it, 

 that the supra-renal vein alone, which courses 

 in the centre of the organ, may be instru- 

 mental to the production of such a cavity, 

 albeit a small one ; so that by injections 

 through this vein the whole medullary mass 

 may frequently be torn up, and converted into 

 a cavity. The covering of the supra-renal 

 capsules consists of areolar tissue. At many 

 points of this covering little processes of are- 

 olar tissue pass directly into the interior of the 

 medullary substance, and thus separate it into 

 portions or lobes of different form and size. 

 These masses of areolar tissue are finally lost 

 in fine bundles, which separate the elementary 

 parts of the gland from each other. We shall 

 return to this again. 



The further composition of the organ which 

 we are now contemplating is better seen in 

 Man than in any others of the Mammalia. 



Fig. 542. 



(After Ecker.) 



a, Nucleus of the contents of the snpra-renal cap- 

 sule from an adult man ; I, Nucleus enwrapped in 

 a fine granular mass ; c, Cell ; d, Nuclear-vesicle 

 of an embryo ; e, two gland-vesicles with their 

 contents from an adult. 



* Gazette Medicale, 1838, p. 57, 



