160 THE AMERICAN MONTHLY [May 



Preservation of Urinary Deposits. — Heretofore the sub- 

 ject of mounting- and preserving- urinary deposits has re- 

 ceived comparatively little attention, perhaps from the 

 fact that no suitable method has been discovered. Speci- 

 mens of urinary deposits, when projierly mounted, are an 

 excellent means of demonstrating- the various pathological 

 elements found in urine. We are indebted to Gumprecht 

 (Centralblatt f. Inn. Med.; British Medical Journal, Sep- 

 tember, 189()) for the following- method, which he finds to 

 be superior to chloroform or g-lycerin: A deposit is first 

 obtained by means of the centrifuge. This deposit is then 

 placed in a concentrated solution of corrosive sublimate 

 and centrifugalized ag-ain. It is then washed, and pre- 

 served in a solution of formal. The hardening in subli- 

 mate may be omitted if no red blood-cells are present. If 

 there is much albumin present, the deposit may be washed 

 with advantage in a normal saline solution. If the urine 

 contains urates, the deposit should be washed with warm 

 water or a concentrated boracic solution. The washing 

 of a deposit by means of the centrifugal machine has long- 

 been in use in the laboratory. No washing is necessar}' 

 if sublimate is not used. The streng-th of the formal solu- 

 tion may vary from two to ten per cent. ^Phe author says 

 that urinary deposits thus preseved can hardly be distin- 

 guished from fresh deposits. Cover-glass preparations 

 may be made, but it is well to wash off the formal. The 

 cells maintain their shape, and the nuclei of the cells take 

 the stain in the usual way. Casts, and especialh' red 

 blood-cells, are well preserved. Fat is readily distin- 

 guished. Micro-organisms are easily recognized even 

 when unstained. — Modern Medicine. 



BACTERIOLOGY. 



Virulent Diphtheria Bacillus of the Conjunctival Sac. — 

 Spronck (Deutsche Med. Woch., 18«)6, No. 3() ) under- 

 took to learn, by means of the specific protective property 

 of Behring's serum, whether the diphtheria bacillus and 



