A New Conception of the Glomerular Function. 581 



The differences are therefore very great. The capacity of Bowman's 

 capsule in the active kidney is nearly three times that of the capsule in the 

 resting kidney, chiefly on account of the big accumulation of fluid within the 

 capsule. 



The volume of the glomerulus has also increased, though only by 40 per 

 cent. Such measurements prove, therefore, that both the glomerulus and the 

 capsule of Bowman are extensible structures, and that a considerable volume 

 of fluid accumulates in the capsule during activity. 



In drawing deductions from these measurements, full attention must be 

 paid to possible alterations occurring after the kidney is excised. To obviate 

 change as far as possible in these experiments, the artery, vein and ureter 

 were ligatured close to the hilum at the instant the experiment was to be 

 stopped, using a single coarse ligature. The kidney was then excised, rapidly 

 weighed, and placed at once in the formalin fixative. If active diuresis were 

 in progress, the kidney at the moment of ligature was hard and tense, but 

 within a few seconds after application of the ligature became quite soft, chiefly 

 on account of escape of blood through the Capsule. We found it impossible 

 to avoid this. The question therefore arises : Does this fall of tension within 

 the kidney substance involve a change in distribution of the fluid contained 

 within the tubule and capsule ? It is possible, for instance, that fluid is forced 

 back from the distended tubule into the capsule. Possibly this may be the 

 cause of some of the increase in volume of the capsule seen in our experiments, 

 but the changes are too great to be wholly, or even largely, explicable in this 

 way. There is yet another post-mortem change we think possible, viz., that 

 before the fixative has time to penetrate and reach the glomeruli, the cells 

 forming the loops die and permit osmotic effects to take place through them 

 between the fluid in the capsule and the blood. Fluid would pass into the 

 blood, and we think it possible that this fluid is so low in salinity as to lake 

 some of the corpuscles, thus producing the vacuolated appearance described 

 above. 



In the same experiment the measurements of the diameters of the proximal 

 and distal convoluted tubules and of their lumina were as follows : — 



Besting. 



Active. 



Proximal convoluted tubule — 



Transverse diameter 



Lumen, diameter 



44-0 



o-o 



43-0 

 19-4 



Distal convoluted tubule — 



Transverse diameter 



Lumen, diameter 



25-4 

 11-0 



31-8 

 21-8 



