176 BACTERIOLOGICAL DIAGNOSIS. 



misleading. A case of ulcerative endocarditis, for 

 example, might be due to streptococci, but might be 

 attributed to staphylococci on the strength of an inade- 

 quate bacteriological examination. For this reason we 

 are chary of recommending this method of diagnosis 

 in any hands other than those of an expert, and must 

 urge the practitioner not to attempt it unless he is 

 prepared to carry out the most thorough disinfection of 

 the skin. 



Requisites: i. A glass pipette such as has been 

 already described. It should be sealed at one end 

 while the other end should be left open and plugged 

 with a loose fitting plug of cotton-wool. The tube must 

 be sterile ; if it has been recently made (and we advise 

 the practitioner to make these pipettes for himself) this 

 will be the case ; if it has been kept in stock for some 

 time it should be sterilised in the dry air steriliser as an 

 additional measure of precaution. The bulb of the 

 pipette should hold at least i c.c., and is to be com- 

 pletely filled with blood. 



2. Needle. 



3. Soap, nail brush, and hot water. 



4. Some reliable antiseptic lotion, such as carbolic 

 acid (i in 20), perchloride of mercury (i in 1000), or 

 biniodide of mercury (i in 500 in methylated spirit). 



5. Alcohol. Absolute alcohol is best, but methylated 

 spirit will do. 



6. Ether or turpentine ; the latter is not so good. 



7. Spirit lamp or Bunsen's burner. 



Process. Scrub the skin, in the region to be pricked, 

 with the nail brush, using plenty of soap and hot water 

 for ten minutes ; then dry the skin and wash it with 

 ether to remove the fat. Next paint on layer after layer 

 of the antiseptic lotion : it is much better to apply a wet 



