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:—1. 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 1 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 (1 in 20), perchloride of mercury (1 in 1000), or 
biniodide of mercury (1 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 
