934 



THE KIDXEYS. 



open to discussion whether all the smaller tubules which open into these 

 arches belong to the convoluted and looped tubules already described, as is 

 believed by the greater number of recent observers, or whether there is not 

 likewise, as is held by Heule and Chrzonszczewsky, a set of small anasto- 

 mosing tubules, some of which may have blind extremities. 



Fig. 655. Fig. 655. DIAGRAM OP THE LOOPED 



URINIFEROUS TUBES AND THEIR 

 CONNECTION WITH THE CAPSULES OF 

 THE GLOMERULI (from Southey after 

 Ludwig). 



In the lower part of the figure one 

 of the larger branching tubes is shown 

 opening on a papilla ; in the middle 

 part three of the looped small tubes 

 are seen descending to form their 

 loops, and reascending in the medul- 

 lary substance ; while in the upper 

 or cortical part two of these tubes, 

 after some enlargement, are repre- 

 sented as becoming convoluted and 

 dilated in the capsules of glomeruli. 



According to Schweigger- 

 Seidel the limbs of the looped 

 tubes are always of unequal size, 

 that which is continued into tho 

 intermediate tubes being tho 

 larger of the two ; and he divides 

 the loops into two sorts, one in 

 which the narrowest portion 

 forms the loop, and another in 

 which, at the loop, the tube is 

 of the diameter of the larger of 

 its two limbs. He likewise 

 points out the existence of occa- 

 sional capsular dilatations, where 

 the looped tubes meet the inter- 

 mediate portions, which, as he 

 remarks, may explain the state- 

 ment of Moleschott, that he had 

 found in mammals capsules com- 

 municating with two tubules. 



The investigations of Chrzon- 

 szczewsky deserve special men- 

 tion, on account of the novel 

 method to which he resorted for 

 the verification of his views, and 

 which promises to throw much 



light on some of the physiological processes as well as on the minute struc- 

 ture of animals. This method consists in the introduction of the colouring 

 matter with which the observed vessels are to be filled into the system of a 

 living animal, either by direct infusion into the blood, or along with food 

 int) the alimentary canal, or by absorption from any of the larger serous 

 cavities. The results of this mode of colouring the vessels and ducts 



