590 



Prof. T. G. Brodie. 



tubules are blocked or obliterated, and have been so for a considerable time, 

 the capsules are often found distended to a volume even ten times greater 

 than the normal volume. In these cases the glomerulus is collapsed and 

 shrunken to a minute structure, which appears as a mere projection into the 

 swollen capsules. 



In my opinion, too, Hill does not allow a sufficient fall in pressure-head 

 between the glomerular capillaries and the tubule capillaries. The efferent 

 blood-vessel of the glomerulus is of small diameter and fairly long. Hence 

 with the exceedingly rapid blood flow observed during diuresis, there must of 

 necessity be a considerable pressure difference between these two capillary 

 systems. I cannot, therefore, agree with Hill's statement : " The pressure of 

 the secretion cannot be normally greater than the pressure in the veins, for 

 otherwise the secretory pressure would compress the veins " ; nor, again, 

 with the statement : " The secretion moves onward, I take it, by phenomena 

 of adsorption." 



At about the same time Filehne and Biberfeld* reasoned that filtration at 

 the glomerular surface was an impossibility, since there were no firm support- 

 ing structures capable of resisting any pressure. They, too, consider that the 

 glomerular capillary pressure is at once transmitted through the whole renal 

 substance, leaving no pressure difference available for filtration through the 

 glomerular surface. While agreeing with them that but a very minute 

 pressure difference can exist between the glomerular blood-pressure and the 

 pressure of the secreted fluid within Bowman's capsule, I am in disaccordance 

 with them, for reasons already stated, in their idea that the glomerular 

 pressure is at once transmitted in undiminished amount to the general renal 

 substance. 



Shortly after I had expressed my views as to the work of the glomerulus, 

 Lamy and Mayerf published a paper in which they suggested that the 

 glomerulus by its pulsation acted as a kind of heart, and by its piston-like 

 movements drove the liquid forward in the tubule, and favoured its discharge 

 by overcoming the friction and the capillarity of the tubule. They do not 

 consider that the glomerulus plays any important part in the secretion of 

 water. If it secretes any at all, this is in their opinion quite a minor 

 role. According to them the glomerulus performs mechanical work solely 

 by virtue of its pulsation, and consequently their view differs widely from 

 mine. I am, in the first place, in wide disagreement with them in that I 

 consider that the main bulk of the water is secreted by the glomerular surface. 

 There is abundant evidence to prove this. I need only refer to the work 



* « Pfluger's Archiv,' 1906, vol. Ill, p. 1. 

 t ' Journ. de Physiol.,' 1906, vol. 7, p. 660. 



