1899] MICROSCOPICAL JOURNAL. 57 



corpuscle is easily overlooked. To produce this appear- 

 ance in red blood corpuscles artificially one needs only to 

 run a little dilute acetic acid solution under the cover 

 glass in a mount of normal blood, when these pale rings 

 will make there appearance. They are usually present in 

 small numbers in the urine. They never form a sediment 

 visible to the naked eye, and are only seen on microscop- 

 ical examination. They are a common constituent of 

 blood casts some of which they completely fill. 



If normal red blood corpuscles are allowed to stand in 

 urine for 48 hours or more, many of them will become 

 washed out, a fact which should not be forgotten in ex- 

 amining old specimens of urine. 



Washed out red blood corpuscles occur in a number of 

 pathological conditions. Von Jaksch names acute nephri- 

 tis, acute congestion of the kidney, and miliary tubercu- 

 losis of the kidney, or its pelvis. Simon Purdy, Diaber, 

 and Peyer speak of their existence, but do not specify 

 the particular diseases. In none of these authorities is 

 there any mention of their presence in the urine passed 

 during or after an attack of pain caused by renal calculus. 

 That they are many times present in this condition is cer- 

 tain, and their presence is of diagnostic value in exclud- 

 ing the causes of acute abdominal pain, such as appendi- 

 citis, gall stone, ulcer of the stomach, intestinal colic, 

 floating kidney, and gastralgia. The urine passed dur- 

 ing and for some days following the attack should be ex- 

 amined fresh. Care should be taken not to confound the 

 spores of certain fungi with washed out red blood cor- 

 puscles ; they are somewhat alike in size, but the spores 

 have more distinct borders and usually contain yellow col- 

 ored granules in their interior. 



In the following cases of renal calculus washed out red 

 blood corpuscles were found in the urine passed subse- 

 quent to or during the attack. 



(1) Examination of urine : Sp. gr. 1026, high color, no 



