MINUTE STRUCTURE OF SUPRARENAL BODIES. 941 



According to Simon, the columns consist of distinct tubes with a limiting 

 membrane ; Ecker and others affirm that no continuous tubular cavities 

 exist, but that rows of closed vesicles, many of them oval in shape, and 

 overlapping each other, are placed in such manner as to resemble tubes ; 

 while Gray believes that the walls of adjoining vesicles are sometimes re- 

 moved by absorption, so that tubular cavities are formed by the coalescence 

 of neighbouring vesicles. Kolliker, however, and other observers, maintain, 

 with more correctness, that the so-called vesicles are merely loculi or cavities 

 in the stroma of the organ, possessing no distinct limitary membrane, and 

 producing the appearance of a tubular structure by their apposition in linear 

 series. The small arteries, entering from the surface, run parallel to these 

 columns, frequently anastomose together between them, and surround each 

 row of vesicles with a fine capillary network. Small bundles of nerves 

 pass inwards in the septa between the columns to reach the medullary part 

 of the organ, and their fibres begin to spread out in the zona reticularis, 

 but do not appear to be distributed to the cortical substance. 



The medullary part of the suprarenal capsule is separated from the cortical 

 part by a layer of connective tissue, the fibres of which are parallel to the 

 two parts, and allow them to be easily separated one from the other in 

 sections prepared for the microscope. In the thinner parts of the adult 

 organ there is no medullary part, or it has shrunk away, and the layer of 

 connective tissue referred to is found separating the deep surfaces of two 

 opposed portions of the cortical part ; but in the young state the dis- 

 tinction of cortical and medullary probably extends throughout the whole. 

 The medullary part is traversed in the centre by venous trunks, which 

 receive the whole of the blood which has passed through the organ. The 

 stroma is delicate, arranged in a reticular manner; the pulpy substance which 

 lies in it is difficult of examination, but consists of cells, differing from those 

 of the cortex in being destitute of oil globules, and some of them branched. 

 The bundles of nerves which pass through the cortical substance run 

 between it and the medullary substance, and then form a copious interlace- 

 ment which extends through the whole of the medullary stroma. According 

 to Leidig and Luschka, the cells of the medullary substance are ganglionic ; 

 and Luschka states that he has found them both connected one with another 

 and with nerve-fibres ; but this view still requires confirmation. Moers, 

 while he denies that the cells of the medullary parenchyma are nervous, 

 describes ganglia on the nerves where their bundles begin to break up. 

 The medullary substance receives its blood by the continuation inwards 

 of the capillary network of the cortex, the blood from which is collected by 

 venous radicles which open into the stems in the centre of the organ. 



Vessels. The suprarenal bodies receive arteries from three sources, viz., from the 

 aorta, the phrenic, and the renal arteries. The distribution of their capillary vessels 

 has already been mentioned. 



The veins, which pass out from the centre, are usually united into one for each 

 organ. The right vein enters the vena cava inferior immediately, whilst the left, after 

 a longer course, terminates in the left renal vein. 



The lymphatics are imperfectly known. Kolliker has seen a few small trunks upon the 

 surface ; and Luschka has, in addition, observed others emerging from the interior in 

 company with the vein. 



Nerves. The nerves are exceedingly numerous. They are derived from the solar 

 plexus of the sympathetic, and from the renal plexuses. According to Bergmann, 

 some filaments come from the phrenic and pneumogastric nerves. They are made up 

 mainly of dark-bordered white fibres, of different sizes, and they have many small 



