1896.] Mr Bles, Nephrostomial Tubules. 75 



it worth while to exhibit before this Society specimens to demon- 

 strate the point. 



A kidney of a common frog (not one year old) was hardened in 

 Hermann's fluid, imbedded in paraffin after gradual impregnation 

 in xylol and paraffin, cut in a series of sections and stained on the 

 slides either with aniline blue-black or by the Biondi-Heidenhain 

 (acid) method. The latter gives plasma well stained with fuchsin 

 and blood corpuscles differentiated with methyl green. A bunch 

 of flagella can be seen protruding through the inner opening of 

 the tubule into a space lined with squamous endothelial cells, and 

 either containing blood corpuscles or standing in open communi- 

 cation with similar spaces on the adjoining sections which do 

 contain blood corpuscles. These vascular spaces can easily be 

 traced into the renal veins. On all four sections shown the peri- 

 toneal opening of the tubule could also be seen. On one section 

 a nephrostomial tubule could be traced from the peritoneum and 

 running towards the flagellate neck of a Malpighian body, but 

 just short of reaching this opening into a narrow space lined 

 with endothelium and containing a blood corpuscle, the space 

 being continuous with venous spaces on neighbouring sections. 



These facts do not stand alone as isolated instances of a 

 channel of communication between ccelom and vascular system. 

 Mr Shipley read a paper before this Society in 1888 (Proc. Phil. 

 Soc, vol. VI. p. 218) in which he cites, with the exception of 

 M. Nussbaum's, the cases occurring in the animal kingdom of 

 such a communication. 



Some of these cases still hold good and amongst them cer- 

 tainly the communication through the peritoneal stomata of the 

 diaphragm in mammals from the great abdominal serous cavity 

 through the lymphatic spaces and ducts into the great veins. 



Physiologically these lymph channels can be compared with 

 what exists in the above-mentioned five forms of Anura. The 

 perivisceral cavity is a lymph space continuous with the cisterna 

 magna lymphatica and passing lymph into it, and there are reasons 

 for thinking that the peritoneal lymph can also pass into the renal 

 veins through the nephrostomies. 



Anatomically considered, the adult Rana fusca can be easily 

 brought into line with the other Amphibia with respect to its 

 nephrostomial tubules when it is borne in mind that the larva in 

 its ontogeny passes through stages in which the tubules have 

 successively relations corresponding (1) to the tubules in adult 

 Urodela, (2) to an indifferent condition still persisting in part in 

 other adult Anura, viz. ending blindly, (3) to a condition which 

 occurs in at least four other forms of Anura and easily derived 

 from the indifferent condition. 



