NERVES AND LYMPHATICS. COAT OF THE KIDNEY. 125 



bly some change. It is certain, that there is some intimate 

 communication between the origin of the ducts, and the 

 radicles of the veins, even in man and the higher animals. In 

 oviparous animals, as has before been observed, the secretion of 

 urine takes place from a portal vein. 



A fine injecting fluid will pass readily from the veins into 

 the uriniferous tubes ; and I find no difficulty in passing air in 

 the retrograde direction, from the ureter into the veins by infla- 

 tion of the former with a large blow-pipe ; the cut extremity of 

 the veins being retained under water, large bubbles of air will 

 be seen to escape from it during inflation. M. Huschke,* was 

 also very successful in passing colored fluids in the same 

 direction, by the aid of the air-pump. The uriniferous tubes 

 were always well injected, the fluid passing in by the orifices 

 on the papillae ; and in most cases the venous plexus in the 

 cortical structure, was also filled. But in no instance, in man 

 or the inferior animals, did he find the fluid passing into the cor- 

 puscles of Malpighi, or into the arteries. 



Fig. 154.f The average weight of a 



healthy kidney in the male 

 according to M. Rayer is 4^ 

 ounces ; in the female 3. The 

 lefc kidney in both sexes is 

 usually larger than the right. 

 In the nephritis albuminosa, 

 (granular disease of Bright,) 

 which is an affection of the 

 cortical or glandular substance 

 only, attended with albuminous 

 urine, the first development of 

 the minute red points, which 

 subsequently become the gran- 

 ulations of Bright, correspond 

 for the most part according to 

 Rayer,J to the highly vascular 

 corpuscles of Malpighi. 



* Isis, torn. xxi. , 



f Fig. 154 is a vertical section of a kidney, in which the ureter is seen en- 

 tering the organ, and dilating into a large sac called the pelvis. The pelvis is 



$ Opcr. citat. 



