ORGANS OF THE BODY. 



521 



to which, at an earlier epoch, the most erroneous views were held. They 

 were supposed by some to end blind in the cortex, and by others to be 

 continuous one with another by means of loops (Huschke, J. Mutter). 

 It was, to be sure, remarked that a peculiar congeries of vessels, known 

 as the glomerulus of Malpiglii was enveloped in a capsule, but its con- 

 nection with the uriiiiferous tubes was denied in the most decided manner 

 by the discoverer, J. Muller. 



In the year 1842, however, this connection was demonstrated by 

 Bowman, who seems thus to have advanced the histology of the organ 

 by several decades. 



Let us now turn for a moment to the mode of termination of the tubes 

 in these capsules, known either in connection with Bowman's or /. 

 Mutter's names. 



It is not unfrequently seen that, on arrival in the neighbourhood of 

 the capsules, the uriniferous tubes (tig. 514) execute a series of very rapid 

 undulations, more or less in one plane. Further, that immediately before 

 opening into the capsule (d) there occurs pretty commonly a constriction 

 on each tubule, more or less marked, and for a greater or less distance 

 (fig. 515, d), and that the limiting membrane of the latter runs continu- 

 ously into the apparently homogeneous tunio of the capsule. The latter 

 has, as a rule, a diameter of about G'1415-0'2256 mm., and spheroidal 

 figure. It may, however, present itself of an elliptical or laterally widened 

 form, or even heart-shaped. 



In a very thin superficial layer of the cortical substance, the cortex 

 corticis of Hyrtl, neither capsules nor glomerules are to be found. They 

 are, however, very numerous in the cortex. Their number, as estimated 

 by Schweigger-Seidel, appears to be, in the kidney of the pig, about 6 to 

 every cubic millimetre, or 500,000 for the whole cortical portion of the 

 organ. 



It is generally held by many observers, among whom Boicman, 

 Gerlach, and Koelliker may be mentioned, that 

 those capsules situated deeper in the kidney are 

 of greater magnitude than the others, and that 

 those nearest the boundary, between the cortex 

 and medulla, have the greatest diameter of all. 



The most difficult point to determine in regard 

 to Bowman's capsules, is the relation to them of 

 the vascular glomerulus and the cellular lining of 

 the interior. 



It was at one time supposed that the vessels 

 simply perforated the wall of the capsule, and 

 that the glomerulus lay naked within the cavity 

 of the latter. Other observers, as Koelliker, for 

 instance, supported the view as far as regarded 

 the perforation, but believed the glomerulus to be 

 covered over by the cells lining the capsule. 

 Another theory is, that the knot of vessels is re- 

 ceived into a depression in the capsule, somewhat 

 in the same way as the lungs are received into 

 the pleura. From my own investigations I am 

 inclined to accept the last view as correct, besides 

 which, it is easiest reconciled with the history of the development of the 

 part (Remak). It must, however, be admitted that the membrana 



Fig. 515. From the kidney of 

 the common snake (after 

 Ecker). a, vas afferens; c 

 glomerulus; b, vasefferens; 

 d, cessation of ciliated cells 

 at the point of exit of tlie 

 uriniferous tube e. 



