244 Mr. Venables on Siliceous Gravel. 



carried whole, without undergoing digestion, to the kidneys, 

 and ultimately make its exit with the urine ? There are, how- 

 ever, a number of objections to such a theory. In the first 

 place, fruit-stones, grape-seeds, &c, which resist the digestive 

 powers, are always voided with the excrement, and have never 

 been observed to pass with the urine. Secondly, before reach- 

 ing the kidneys # they must pass with the chyle into the circu- 

 lating mass, and hence go the round of the circulation. Now, 

 we cannot conceive such hard gritty irritating matter pervading 

 the more delicate tissues and finer vessels, without exciting 

 violent inflammation and speedy disorganization. 



Upon reflection, and after close attention to the circum- 

 stances, I am disposed to attribute the appearance of this 

 matter to a morbid condition of the kidneys themselves, either 

 generating the substance itself by a morbid process, or else 

 separating it from the drink or aliment, and aggregating it into 

 the masses and forms under which it appears mixed with the 

 urine. 



In support of this view, I would observe that there is mani- 

 fest disease in the kidneys as well as bladder, and a morbid 

 condition of the uterus. There is evident tendency to urinary 

 affections, attended, as is mostly the case under such circum- 

 stances, with an impaired state of the general health. There 

 is a great analogy between the two cases, and between the 

 general symptoms in each. 



There is, however, one fact clearly established by this paper, 

 namely, that siliceous sand may — however introduced, or 

 whencesoever its origin — form, in some cases, a portion of 

 gravel, and from which we may infer that it may sometimes 

 form a portion of urinary calculi. 



* There can be no doubt that fluids sometimes reach the kidneys and 

 bladder by a less circuitous route than the round of the circulation. The 

 means by which this is effected, are at present involved in so much ob- 

 scurity, that nothing decisive has been determined relative to this ques- 

 tion. It has been supposed to be accomplished by transpiration, and if 

 it has so, it is evident that silex in the solid form, though in a state of 

 ever so minute mechanical division, could not be thus conveyed to the 

 kidneys or bladder. 



