BACILLUS OF TUBERCULOSIS. 295 
‘‘The range of the patient’s temperature is ascer- 
tained by taking it at 8 a.M., 3 P.m., and 8 p.m. for 
three or four days before making the test. The first 
injection should not exceed 0,5 mg., and if any fever 
is habitually present should be even less, and is best 
given early in the morning or late at night, as the 
typical reaction usually begins, in my experience, 
within six or twelve hours. Such a small dose, while 
it will often be sufficient to produce the looked-for rise 
of temperature, has, under my observation, never pro- 
duced unpleasant or violent symptoms. An interval of 
two or three days should be allowed between each of the 
two or three subsequent injections it may be necessary 
to give, as reaction in very rare cases may be delayed 
for twenty-four or even thirty-six hours. On the third 
day a second dose of 1 mg. is given, and if no effect is 
produced a third, of 2 mg., three days later. In the 
great majority of cases of latent tuberculosis an appre- 
ciable reaction will be produced by the time a dose of 
2 mg. has been reached. If no effect has been caused 
by the tests applied as above I have usually gone no 
further, and concluded that no tuberculous process was 
present, or at least not to a degree which need be taken 
into account in advising the patient or which would 
warrant insisting on a radical change in his surround- 
ings and mode of life. If some slight symptoms, how- 
ever, have been produced by a dose of 2 mg., it may 
be necessary to give a fourth injection of 3 mg. in order 
to reach a positive conclusion. Nevertheless, it should 
be borne in mind that in a few cases the exhibition 
of even larger doses may cause reaction and indicate 
the existence of some slight latent tuberculous lesion, 
and the test should not, when applied within the 
