ADDENDA TO THE DISEASES OF THE KIDNEYS. 387 



Colds also seem to play an important rôle in the development of 

 hemoglobinuria in the subjects of our other domestic species. 



Inflammation of the Pelvis of the Kidney : Pyelitis. 



Pyelitis preseuts much more interest for the pathological anat- 

 omist than for the clinician. It is almost always secondary, con- 

 secutive to other diseases of the urinary tract (nephritis, cystitis, 

 etc.) ; moreover, intra-vitam diagnosis is only possible in the minor- 

 ity of cases. We shall thus be limited to a brief description of 

 this disease. 



Etiology. Inflammation of the pelvis occurs ordinarily by an 

 extension of nephritis or cystitis to the mucous membrane of the 

 kidney pelvis (pyelo-cystitis and pyelo-nephritis). It is quite fre- 

 quently produced in the course of infectious diseases and poisonings^ 

 when the infectious or toxic matters which are eliminated by the 

 kidneys exert an inflammatory action upon this mucous membrane 

 (glanders, tuberculosis, acid diuretics). Foreign bodies, renal cal- 

 culi, or sand and sedimentary deposits (renal lithiasis) occasion at 

 times a more or less intense inflammation of the mucous membrane 

 of the renal pelvis (calculous pyelitis) ; according to Bruckmûller, 

 the peculiar sediment which exists in the normal urine of some 

 horses may act in the same way.^ The presence of the giant eustron-^ 

 gylus in the renal pelvis (dog, horse, and ox), or stagnation of the 

 urine due to a mechanical or dynamic retention in the pelvis, and 

 its consecutive decomposition, are also causes of pyelitis. When 

 urinary stagnation is prolonged, the kidneys become atrophied and 

 its substance undergoes " cystic rarefaction " (hydronephrosis). 



Pathological anatomy. According to the causes, degree, and 

 duration of the inflammation, we may distinguish simple, acute, or 

 chronic, purulent, croupous, diphtheritic, or calculous pyelitis. In sim- 

 ple acute pyelitis the mucous membrane is tumefied, red, sometimes 

 ecchymosed, and covered with a mucous exudate which is rich in 

 desquamated epithelial cells ; in the suppurating form this exudate 

 is almost exclusively composed of white corpuscles. Renal calculi 

 produce circumscribed inflammatory centres upon the mucous mem- 

 brane, which become necrotic and are transformed into ulcers covered 



1 Urinarj deposits are not rare among birds. They may be found in the cloaca^ 

 the ureters, and kidneys; in these two latter organs they appear in the shape of 

 concretions or whitish striae. (Dr. Larcher : Mélanges de Pathologie comparée, 1878.) 



— N. D. T. 



