CORRESPONDENCE. 
391 
Gallipolis, Ohio, Jan. 12, 1878. 
To the Editor American Veterinary Review: 
Sir : Since the summer of 1873 I have been studiously engaged in 
endeavoring to elucidate what, strange to say, has been an almost en¬ 
tirely neglected field of scientific labor—that is, the minute structure of 
urinary calculi. My interest, originally, was excited by the researches 
of Mr. Carter, whose work on the ‘‘Microscopic Structure of Calculi ” 
is the only treatise on the subject in the hands of the profession. During 
the past four years I have had an exceedingly instructive experience in 
lithotrity, and my studies have been largely based upon the fragments my 
operations have furnished. Lately, however, some of my professional 
friends have permitted me to examine calculi which they have either 
removed from patients, or which have been spontaneously voided by 
individuals under their care, and in this way the number of specimens I 
have examined has been greatly augmented. I now desire to study the 
minute structure of certain calculi which form in the urinary passages 
of the horse. I do not see how I can explain the reason for this in¬ 
vestigation better than stating the following undoubted, but little known, 
facts : When two saline solutions, which are calculated to produce by 
double decomposition an insoluble carbonate of lime, are allowed grad¬ 
ually and slowly to intermix in a viscous medium, there are formed by 
the union of nascent salt with the dissolved gum or albumen, not crystals 
of the carbonate, but small, firm, rounded bodies, which are possessed 
of a concentric and radiate structure, and which, while disposed to ad¬ 
here to any surface already existing, also tend to meet and blend to¬ 
gether, so as to lead to the construction of a laminae series. These 
forms of carbonate of lime I have on two occasions found in human 
vesical calculi—they are very rarely found in human urine—yet these 
structures are quite common in the urine of the horse, and my object 
in addressing you and your readers is, that I may induce some veterinary 
surgeon to allow irte to examine his specimens, in order to determine 
whether these peculiar bodies exist in the calculi occasionally found in 
the bladders of horses. I will further state that the best way to send 
calculi to me is by mail; that I will promptly acknowledge the receipt 
of specimens, and hold the same subject to the owner’s order; and, 
finally, that in publishing my researches I will give due credit to every 
gentleman who aids me in my investigations. 
Trusting that your readers may take an interest in the elucidation 
of this point, and aid me in the manner indicated, I am, 
Yours sincerely, Reuben A. Vance, M. D., 
Gallipolis, Gallia County, O. 
