218 



SPECIAL HISTOLOGY. 



Fig. 254. 



phrenic nerves. In Man, in the right suprarenal gland, I 



have counted thirty- three trunks, 8 of ± — ^" , 5 of ± — i'", 

 7 of £— £'", and 13 of ^— &'", and found 

 that, without exception, or at all events 

 in a very preponderating proportion, they 

 were constituted of dark-bordered, finer 

 and medium-sized, or even thick fibres ; 

 were whitish or white and furnished with 

 isolated, larger or smaller ganglia. They 

 are especially apparent on the inferior 

 half and inner border of the organ, and 

 appear to be all destined for the medul- 

 lary substance, in which, at least in 

 the Mammalia, an extremely rich plexus 

 of dark-bordered, finer fibres occurs, in- 

 closed in the trabecules and connective 

 tissue, their terminations, however, being 

 nowhere perceptible. In Man, the me- 

 dullary substance is, in most instances, so 

 altered, that the nerves cannot be traced 



farther than to their entrance into it, it being impossible to 



follow their farther distribution. 



§ 195. 



Physiological remarks. — The suprarenal glands are deve- 

 loped simultaneously with the kidneys and independently of 

 them, from a blastema derived from the middle germinal la- 

 mella (Remak), the first appearance and growth of which is 

 unknown, and are originally larger than the kidneys. In the 

 third month the two organs are of equal size ; in the embryo 

 at six months, the weight of the suprarenal capsule is, to that of 

 the kidney, as 2 to 5, in the mature embryo as 1 to 3, in the 

 child at birth as 1 to 8 (Meckel). In other Mammalia the 

 suprarenal glands are, from the first, smaller than the kidneys, 

 and increase in the same proportion with them. Little is 

 known with respect to the histological development of the 



Fig. 254. Transverse section of the suprarenal body of the Calf, x about 15 

 diam., treated with soda: a, cortex ; b, medulla; c, central vein surrounded with 

 some cortical substance ; d, three entering nerves ; e, nerves, and their distribution 

 in the interior. 



