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Nachdruck verboten. 



The Kidney Cells of the Frog in a Phagocytic Role. 



By W. M. Smallwood. 



(From the Zoological Laboratory of Syracuse University.) 



With 8 Figures. 



These observations were made on Rana pipiens while it was being 

 utilized for class study. In attempting to demonstrate the corpora 

 adiposa, it could not be found and the specimen was placed in formalin 

 for further study. 



Upon dissection, the two kidneys were found in their normal 

 position and, so far as the unaided eye could detect, normal in struc- 

 ture. The corpora adiposa on the right side was easily found although 

 small; but on the left side it had an unusual outline which was the 

 reason for its being overlooked the first time. 



The regular corpora adiposa is not of constant shape. Figure 1 

 is a drawing which shows the main outlines of a normal one. There 

 is usually an irregular mass from which extend several processes, some 

 straight and unbranched, others sinuous and branching. The whole 

 mass is of a yellowish color with the blood vessels showing prominently 

 on the surface. Figure 2 shows the left corpora adiposa of the frog 

 in question. It is roughly rectangular in outline with a slight enlarge- 

 ment at one corner. This is the end that was attached to the kidney. 

 From the distal end there are two short processes which are the only 

 structures to suggest that this is the corpora adiposa. The size of 

 the main mass is 15 mm long and 9 mm greatest width. The color 

 was a dark red. 



When the corpora adiposa shown in Figure 2 was sectioned inter- 

 esting changes were seen to be taking place. If the freshly cut sections 

 after being placed on the slide, were warmed sufficiently to melt the 

 paraffin and then at once examined, many particles could be seen 

 floating around. As soon as the sections were stained and examined, it 

 was seen that there were so many blood corpuscles as to obscure the 

 other tissues. These blood corpuscles were of various shapes, many 

 without a nucleus which suggested that they were undergoing de- 



