166 Points in the Histology of the Human Kidney. 



presented to the observer in every possible variety of segment, and 

 yet there is absolutely no difference whatever in their appearance. 



This circumstance is obviously inconsistent with the view that 

 the cells form either one or two thin laminae, one of which is said 

 to line the capsule, and the other to envelop the vessels ; the former 

 would be removed from the surface by the act of section, and there- 

 fore no longer seen ; the latter would show the outline of a filmy 

 crust of cells surrounding the enclosed vessels — an appearance 

 opposed to the actual facts and conditions of the parts. 



The malpighian body and the urinary tubule constituting 

 as they do together the proper structure of the kidney, errors 

 in their description like those under consideration, involve nothing 

 less than a corresponding misconception of the physiology of the 

 organ, and as a further consequence of that of its pathology; 

 this brings me back to the point from which this communication 

 started. 



It is not necessary here, nor is this the proper place to examine 

 the history of disease of the kidney ; but it may with propriety be 

 stated that a very important part of it deals with the function of 

 the malpighian body as hitherto conceived ; and that the presence 

 of casts of the tubuli uriniferi in the urine is taught as indicating 

 a variety of degrees of departure from the healthy condition of 

 these tubes. Though this latter doctrine is indisputable in a 

 general sense, it is clear it must be modified in so far as certain 

 of the imports of these casts are based upon the existence of the 

 central epithelial canal ; since they must be fallacious if the legend 

 of that canal is itself the fable I have shown it to be. 



Questions of more than ordinary interest, both to histology and 

 to the theory and practice of medicine, are involved in these issues ; 

 and such being my justification in bringing the subject forward, I 

 trust that these strictures may be regarded as a challenge to those 

 most capable, to further investigation of the organs. 



