810 



SUPRA-RENAL CAPSULES. 



is filled with a more or less clear fluid. Never- 

 theless, in Man, the gland-vesicles are generally 

 completely filled with the morphological con- 

 stituents of their contents. 



As regards the thymus, we have lately had 

 Simon's researches extended by Ecker, Ger- 

 lach, and Schaffner. The gland-vesicles here 

 likewise enclose similar contents. The quan- 

 tity of the elementary granules seems to be 

 very variable, and nuclei form the greater part 

 of the contents. In general, cells occur but 

 very sparingly. According to Simon, their 

 number is increased by involution of the 

 organ, in which case, also, fat molecules are 

 wont to appear in place of the elementary 

 granules. As to the gland-vesicles, they 

 deviate from those of the vascular glands 

 hitherto described. In the embryo of the 

 Adder and of Birds, Ecker saw many completely 

 shut gland-vesicles, which everywhere passed 

 into sacculi by pouchings of their membrana 

 propria. In the human thymus, and that of 

 Mammalia generally, only a few vesicles of 

 this kind were found, and the tunics of these 

 exhibited the same condition. Thus the 

 thymus gland exhibits a similarity with the 

 clustered glands ; but is distinguished from 

 these by the want of an excretory duct. And 

 these differences of the gland-vesicles, toge- 

 ther with the great number of the nuclear 

 structures, somewhat distinguish the thymus 

 from the supra-renal and thyroid glands. 



The structure of the spleen is even more 

 different, if it be allowable to decide upon 

 this organ, which is so uncommonly diffi- 

 cult of examination, from a few observations 

 of a somewhat contradictory tendency. It is 

 only the well-known Malpighian corpuscles 

 which can be regarded as glandular struc- 

 tures. In fact, this opinion would seem to 

 be correct, since Ecker found a delicate mem- 

 brane enclosing the vesicles. Nevertheless, 

 lately, an opinion has been put forth on many 

 sides, and based on continuous research, that 

 the Malpighian corpuscles are not closed 

 vesicles, but stand in connection with the 

 lymphatics, so as to constitute only vesicular 

 dilatations of these vessels. This view, which 

 is maintained by Gerlach and Schaffner, is 

 especially corroborated by the fact, that the 

 contents of the splenic vesicles differ from 

 those of the other vascular glands, and closely 

 approximate to those of the lymphatic ves- 

 sels. Thus we remark in their contents, cell 

 nuclei in very predominant quantity, the dia- 

 meter of which amounts to 2-1000ths of a 

 line. These nuclei appear sometimes smooth, 

 sometimes granular ; they often exhibit one 

 or two nucleoli, while in other instances they 

 have none. Roundish cells of 4 to 5-1000ths 

 of a line, and closely surrounding a nucleus, 

 may also be remarked in sparing quantities. 

 The above-mentioned relation of the Malpi- 

 ghian corpuscles to the lymphatic vessels is 

 probably supported by another circumstance. 

 Another cell formation may be found in al- 

 most every spleen, and certainly in the splenic 

 vesicles also. They are large, globular cells, 

 measuring from 5 to 10-lOOOths of a line, 



and with contents of a very different kind ; so 

 that from this fact one might conjecture that 

 the}' form a number of very different struc- 

 tures, which, however, are connected with 

 each other by transitional forms. Thus a 

 part of these cells contain more or less dark 

 elementary granules ; another part enclose 

 larger yellowish, or yellowish brown and 

 tuberculated corpuscles ; while finally, other 

 cells contain, with the latter corpuscles, one 

 or many completely developed blood corpus- 

 cles. This group of cells is susceptible of a 

 double interpretation. In the first place, 

 effused blood corpuscles may be enclosed by 

 a cell membrane, and may be broken up into 

 elementary granules in its interior. This 

 view has been taken by Kolliker*, and is 

 supported by pathological appearances. But 

 the process may be exactly the reverse ; the 

 blood corpuscles may be developed in the 

 interior of the cells, and then, after the burst- 

 ing of the cell wall, become free. And should 

 this latter view, which is especially maintained 

 by Gerlachf, ultimately turn out to be correct, 

 then we shall have in the Malpighian vesicles 

 of the spleen a new development of blood 

 corpuscles, just such as occurs after another 

 scheme, in the other district of the lymph 

 and chyle system. So that the spleen would 

 be an organ especially serving for the develop- 

 ment of blood corpuscles, and the old ex- 

 planation set forth by Hewson would be the 

 correct one. But if the process be that which 

 Kolliker supposes, the spleen will exercise the 

 function of destroying the blood corpuscles. 

 In any case, it is worthy of notice, that no 

 such cells containing blood corpuscles occur 

 in the other vascular glands. Gerlach could not 

 discover them in the thymus gland, and they 

 would scarcely have escaped Ecker's careful 

 observations of the supra-renal capsules. So 

 likewise, in a number of examinations of 

 supra-renal capsules, it is impossible to find 

 the least trace of their presence. Therefore 

 by all this the spleen is greatly distinguished 

 from the other vascular glands. Such great 

 differences of structure and contents will not 

 allow us to attribute a like function and a like 

 secretion to all these organs. Certainly we 

 cannot at all state of what kind these differ- 

 ences of secretion are, since the materials 

 prepared by these vascular glands are, as far 

 as regards their composition, completely ne- 

 glected : but that such differences must 

 exist, I think microscopic research will quite 

 warrant us in saying. In this respect the 

 thyroid gland and supra-renal capsule agree 

 most nearly together, since in general terms, 

 there is a great correspondence in their struc- 

 ture. And, as the spleen is the widest se- 

 parated from them, so it is not unlikely 

 that future research may remove it from 

 amongst the vascular glands. 



Since the chemical constitution of the se- 

 cretion is unknown to us, we are unable to 



* Vide Landis's Dissertation, apparently under 

 Kb'lliker's direction, Beitrage zur Lehre liber die 

 Verrichtungen der Milz, Zurich, 1847. See also the 

 article SPLEEN. 



f Loc. cit. 



