344 THE TUBERCLE BACILLUS 



Pour the urine into a conical glass vessel and add a small crystal of thymol 

 or camphor. If there is an abundant deposit of pus homogenize the deposit 

 and centrifuge. If only a small deposit is formed, decant the supernatant 

 liquid and prepare films with the deposit. If after 24 hours there is only a 

 minimal deposit, decant the upper part of the liquid, add an equal volume of 

 95 per cent, alcohol to the few cubic centimetres of liquid remaining in the 

 vessel, mix and centrifuge. 



<v 

 ' 







FIG. 212. Tubercle bacilli in urine. (Carbol-fuchsin and methylene blue.) 

 (Oc. 2, obj. Ath, Zeiss.) 



When a urine contains only a few cells the deposit adheres badly to the 

 cover-glasses and is liable to be washed off in the staining process. This 

 difficulty is especially encountered when the urine yields a large bulky pre- 

 cipitate of crystals of urates on centrifuging. To overcome this, Trevithic 

 recommends washing the deposit several times in distilled water but the 

 method does not seem altogether reliable. The author prefers to heat the 

 urine to 40-45 C., centrifuge and wash the deposit once with distilled water 

 at 45 C. When the deposit is very small, it may be mixed with 2 or 3 drops 

 of a mixture of fresh egg albumin and distilled water (1-3) which fixes the 

 deposit on the slide better. 



Jousset's method has been utilized for the detection of the tubercle bacillus in 

 urine. Add some blood plasma to the urine, digest the clot which forms with artificial 

 gastric juice (p. 340) and centrifuge. Examine the deposit for tubercle bacilli. It 

 must not be forgotten that this method more than any other is liable to lead to error 

 on account of the presence of other acid-fast bacilli particularly of the smegma 

 bacillus which is easily mistaken for the tubercle bacillus. 



The only certain method of detecting the tubercle bacillus in urine is to 

 inoculate a guinea-pig. When the urine can be collected aseptically and is 

 not contaminated either with the colon bacillus or other pyogenic organisms 

 a few cubic centimetres may be inoculated into the peritoneal gavity of a 

 guinea-pig. In the contrary case the urine should be inoculated sub-cutane- 

 ously. It has also been recommended that the deposit obtained on centri- 

 fuging the digested clot in Jousset's method should be inoculated. 



H. Excreta. 



[Acid-fast bacilli having the morphological properties and staining reactions 

 of the tubercle bacillus can often be seen in films made with the excreta of 



I 



