GLANDS. 113 



this membrane has been endowed with the quality of strongly resist- 

 ing injurious influences, and even powerful chemical reagents. In 

 virtue of this last-named property, we are enabled to show clearly 

 the tubes of the kidney, by certain processes hereafter to be de- 

 scribed." Trans. N. Y. Acad. of Med., Vol. I. part IX. p. 379. 



In relation to the nature of the renal epithelium, it is stated 

 (p. 380) that "most of the epithelial cells are polygonal, although 

 many are oval, and others of a rounded or irregularly rounded 

 shape." . . . " It is extremely difficult to meet with specimens of 

 the kidney sufficiently healthy to exhibit the perfectly normal 

 epithelium." ..." The epithelium very soon becomes changed 

 from decomposition, or by the action of water, which expands the 

 cells, and sometimes causes them to burst, when the tubes are found 

 to contain merely nuclei and granular matter. In examining the 

 epithelium, it is therefore very important to obtain the kidney in as 

 fresh a condition as possible, and instead of water, to use a solution 

 of albumen in water, or urine." In conclusion, the opinion is 

 expressed, that all the appearances presented by the renal cells 

 differing from the characteristics of pavement, or tesselated epithe- 

 lium, are the result either of decomposition or disease, (p. 381.) 



As to the presence of cilia upon the epithelial cells of the kidney, 

 it is admitted, in fishes and the amphibia. To determine the ques- 

 tion as to its existence in the mammalia, he "resorted to the large 

 establishments, in this city, for killing oxen, sheep, horses, dogs, 

 rats, etc., and examined the kidneys immediately after the death of 

 the animal." ..." Some of the scraped substance of the kidney 

 was gently agitated, in a test tube, containing a solution of albumen, 

 and a drop of this fluid was then placed under the microscope. 

 Thin sections were also used. In some animals no motion could be 

 perceived, but in the dog I observed currents taking place, in the 

 fluid, and also within the uriniferous tubes. The epithelial cells 

 would frequently disengage themselves from the sides of the tube, 

 and pass along for a considerable distance, and after emerging from 

 the mouth of the tube, would assume a rotatory motion. Sometimes 

 nearly all the epithelial cells would pass out of a tube, in the space 

 of fifteen or twenty minutes, leaving it almost denuded of its internal 

 epithelial lining. I have also seen isolated cells, having a vibratory 

 or rotatory movement. These appearances I have noticed upon 



