THE Um.VARY APPARATUS. 495 



.1, v. 1 iju'il in the medullary tissue. As these nerves do not leave the medullary 

 sulisMm -r, and as, besides, its cellular elements appear to bo of the same 

 iiiiture u> tin- multipolar gunglionic cells, it is presumed that the nervous 

 fibres emerge from these globules, and that the medulla acts as a ganglionic 

 nervous centre. Though Leydig fully believed the internal portion to be 

 of a nervous character, he thought another function might be attributed to 

 the cortical, in consequence of its being most frequently of a fatty nature. 

 Bergmann was the first, in 1839, to class those organs with the nervous 

 system, and Ilemak, in 1847, by his researches in embryology, was 1 .1 tn 

 group them with the sympathetic ganglia, and named them nervous glands. 

 Injury to the dorsal portion of the spinal cord causes congestion and 

 hypertrophy of the supra-renal capsules. In a watery solution of the 

 r n tif;d portion, a rose-tinted substance has been discovered, which changes 

 to green with persalts of iron.) 



Development. These bodies are relatively larger in the foetus than the 

 ulult. though this difference does not influence their structure. 



Fi.\ IIONS. Their uses are still unknown; they are ranked in the 

 category of blood- vascular glands, along with the spleen and thyroid body, 

 whose functions are also not yet ascertained. (Leydig is of opinion that 

 these bodies should be regarded as belonging to the nervous system.) 



DIFFERENTIAL CHARACTERS IK THE URINARY APPARATUS OF OTHER THAN SOUPED 



ANIMALS. 



1 . Kidneys. In other than Soliped animals, the renal glands are simple or multiple, 

 or in other words, simple or lobulated. In the Ox, the kidneys have an elongated shape 

 from before to behind, which is altogether characteristic; and, in addition, they 

 preserve during life the lobulated form only seen in the other animals during intr.i- 

 uterine existence. Each agglomeration is composed of from fifteen to twenty secondary 

 kidneys; but the pelvis is not formed in the centre of this agglomeration, being carried 

 :ilt>_r. -thc-r outwards, and occupying an excavation in the inferior face of the organ, which 



nts tin- hilus. This cavity is divided into as many short, wide prolongations the 



are principal lobules; the uriniferous tubes from each lobule open 



-mall papilla, which projects into the bottom of the calyx. This papilla is, therefore, 



nothing more than the crest of the simple pelvis in the kidney of Solipeds (Fig. 256). 



In ill- >''.-,-, tin- kidneys are not lobulated, and the pelvis is carried to the inner 



. :i> in tin- 1 : 



The kidneys of the Pig are simple and voluminous, and their pelvis is disposed as in 

 tin- Horse. ( There are 10 or 12 papilke, and as many calic. 



In the Doq and Cat, there are no calices absolutely comparable with those of 

 Kumiiiants. The pelvis is simple, and presents at the bottom a single, large, elongated 

 tn!*-icle, that has at its base some very short projections or pill ir.-. 



2. Bladder. The most ini|x>rtnnt dillerence in the bladder of the domesticated 

 aniniii: in the extent <>f the development of its jn-rit meal envel<>|>e. In uon- 



i a-iirnals this covers all the organ to the neck ; the ligaments are also very short, 

 iin<l the vis us may be easily projected into the abdominal cavity. The bladder is thin, 

 : a considerable capacity in Jtuinimtnt* and the /'i/ ,- in the Dog, on the contrary, 

 it has a very thick muscular layer, iU fibres forming distinct faacienli. e-p. chilly when 

 in a state of retraction. (In Ruminants, the orifices of the ureters are near each other ; 

 at the fuiidn.s the mucous membrane t>h'>\\s u .-mull fosa which is continued by a narr>w 

 canal that terminates in a cul-de-tac, and constitutes a free appendix about half an inch 

 l"ii.'. si-i'l i.f the thiekness of a goose-quill.) 



^'ij.rii-rrnal eaptukt. These small organs are discoid in the Shffp and Pig, 

 nn in tli-- It'xj. In the Ox, they are situated at a certain di.-tunce in bant 

 kidne\ s, ami t -ir shape is like that of these bodies in the Horse; though they are a little 

 Tri.-ted in the middle, and slightly curved. 



In /;/<(?-,. the kidneys "are 1-nlged at the same height, behind the peritoneum, 

 inline li.it. -ly ].-t< ri<>r to the lungs, and in the lumbar and pelvic regions, where they 

 < -cupy several f<>ss;e e.v.i\ate 1 in the up|-T face of the p--lvi.s. Their form is irr. -uhir 

 and more or less elongated, depending \\\>\\ the tones and other part* to \\hi.-ii they are 



