Points in the Histology of the Human Kidney. 163 



that they have no existence, and that no trace of them or any- 

 other kind of opening whatever is to he found. The tuhe is there- 

 fore actually completely filled by the pulpy granular mass in 

 question, so that no canal, fissure, or space of any kind exists for 

 the passage of the secretion. 



Doubts may occur to some in the absence of the central canal or 

 other space, as to the mode in which the secreted urine passes along 

 the tubuli uriniferi : but there is a simple explanation at hand which 

 not only clears up the difficulty, but at the same time indicates more 

 satisfactorily than hitherto the modus operandi to some extent, of 

 another important function of these organs. 



Let us suppose that the water finds its way from particle to par- 

 ticle along the tube by capillary attraction, or some analogous force, 

 and we shall have at once an obvious and sufficient method of 

 transit. And assuming that the pulpy mass filling the tube is per- 

 meated with water in this way, it is probable the washing away of 

 the saline matters it is its function to separate, would be more easily 

 and thoroughly accomplished than would be the case if the water 

 merely ran over its surface, as in the presence of any form of 

 canal. 



Observation and theory therefore are so far at one in ignoring 

 the orthodox teaching upon these points in renal histology. 



But fortunately observation only is required to settle these 

 questions, and everyone may submit them to the test of the micro- 

 scope for himself. The only conditions stipulated for are, that the 

 section of kidney should be fresh, unmanipulated, and examined in 

 glycerine. 



I think it essential to insist upon this simple method of examina- 

 tion, because, while it is sufficient, it obviates all doubt and silences 

 all question as to the tissues being seen as nearly as possible in 

 their natural condition. 



This point of departure in every histological inquiry is a sine 

 qua non ; and it is not until we have placed ourselves in full pos- 

 session of the facts relating to general characteristics as they may 

 be learnt from such modes of procedure, that we may venture 

 gradually and by successive steps to the more elaborate manipulation 

 that may be required for the display of any new tissue or organ in 

 its minuter detail. 



It was probably due to such want of precaution as this that the 

 malpighian body was, and still is, regarded by Bowman and his 

 school as composed, except as to the capsule, entirely of a free tuft of 

 capillary blood-vessels. The vessels of the kidney, apparently with- 

 out preliminary examination of the organ, were at once injected, 

 and with such violence was the process conducted, that in some 

 instances the injecting fluid was actually forced out of the capil- 

 laries into and along the entire length of the tubuli uriniferi ! 



