STONY CONCRETIONS IN THE PELVIS OP THE KIDNEY. 61 



furnish a nucleus for a phosphatic shell. From the experiments of 

 Studensky, who inserted foreign bodies into the bladders of dogs 

 and put lime into their food, it would seem that an excess of lime 

 in the food predisposes toward phosphatic calculi. Even the phos- 

 phates which properly exist in the body may by morbid and exces- 

 sive transformation produce stones in the urine, as sometimes hap- 

 pens in osteomalacia. 



Gravel and stones form at all ages of life. In childhood, how- 

 ever, the disposition toward stones perhaps through uric-acid in- 

 farction of the new-born seems the greater ; and in old age it is 

 also common. That men should suffer more often than women 

 would seem to be because of their different modes of life. How 

 much geological and climatic influences have to do with endemic 

 tendency to stone in certain countries, as England, Holland, and 

 parts of Germany, has not been made clear. 



Concretions rarely form in the kidney-substance proper ; but 

 cases like those of uric-acid infarction of the new-born have been 

 seen in the adult, in which uric acid was found after gout, hgema- 

 toidin crystals after haemorrhage, and bile-pigment after jaundice. 

 Carbonate of lime, too, has been met with. Real stones are also 

 found as very great rarities in the kidney proper, or rather in por- 

 tions of the dilated urinif erous tubules. The ordinary seat of gravel 

 and of stone is in the calyces or pelvis of the kidney. The smaller 

 stones are roundish ; larger ones mould themselves to the shape of 

 the region which they occupy, so that stones of the calyx acquire 

 a pyramidal form.] 



Stony concretions form in the pelvis of the kidney, probably 

 under the same conditions which cause them to form in the bladder. 

 When treating of vesical calculus, we shall discuss the pathogeny 

 and etiology of these calculous formations more fully. Many, and 

 perhaps the majority of stones in the bladder, originate in the pel- 

 vis of the kidney, and pass thence through the ureters into the blad- 

 der, where they increase in size by precipitation from the urine. 



ANATOMICAL APPEARANCES. In cases of uric-acid infarction, 

 upon section through the pyramid, we see delicate yellowish-red 

 stripes running in the direction of the tubules. Upon microscopic 

 examination, these tubules are found to be filled with a blackish, 

 coarsely-granular material. Upon the addition of an acid, these 

 masses disappear, and are replaced by crystals of uric acid. Ac- 

 cording to Virchow, dilatation of the tubules and the formation of 

 cysts in the kidney of the f 03tus may arise from permanent obstruc- 

 tion of the efferent tubules. In the haemorrhagic-pigmentous in- 

 farction we also see red streaks, with a tinge of yellow in them, in 



