ri8 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



large as yeasts ; the different cocci of each group usually vary in 

 size amongst themselves, the younger forms being the larger. 

 Most of them stain by Gram, but this test is hardly necessary, 

 as they may be readily recognised in unstained wet prepara- 

 tions. 



They occur in profusion (often mixed with yeasts) in many 

 cases of simple dilatation of the stomach, though not in all. 

 They occur in other conditions, but are very rarely found in cases 

 of carcinoma, and this is the only importance attaching to them. 



THE URINE 



The more important investigations in which the urine has to 

 be examined have been mentioned already. See p. 62 (tubercle 

 bacilli) and p. 87 (gonococci). 



Methods. — Where the examination is to be microscopical and 

 not cultural it is not usually necessary to use a catheter specimen. 



The urine is to be passed directly into a sterilized vessel (or at 

 least a clean and dry one), the first portion being passed into 

 another vessel and rejected. 



The examination should commence by the inspection of a 

 hanging-drop preparation, first under the ^, then under the ^. 

 This will enable you to recognise the presence of motile bacilli, 

 streptococci, other cocci, etc. ; pus, blood, epithelial cells, etc., 

 and crystals. 



In most cases it is not absolutely necessary to centrifugalize 

 the urine, since the bacteria are commonly present in large 

 numbers, but it is an advantage when this can be done. It is 

 not advisable to allow the urine to deposit spontaneously, as there 

 are many chances of accidental contamination, and many common 

 bacteria grow with great rapidity in urine. 



Then pass on to film preparations, preferably from the centri- 

 fugalized deposit. Prepare films in the ordinary way and stain by 

 Gram, counterstaining by dilute carbol fuchsin. This will enable 

 you to study the organisms more closely, and to see whether 

 they retain Gram or not : most of them do. The staphylococcus 

 (which appears in the urine mostly as diplococci) and the M. uvea 

 do so, and the gonococcus and the gonococcus-like diplococcus 

 which causes cystitis are decolorized. 



Where cultures are required, a catheter specimen must be used. 



