DIAGNOSIS OF TUBERCULOSIS 487 
1 to 3 or even 4 cin., the former being the more common. The maxi- 
mum intensity is usually reached within forty-ei(i:ht hours, the first 
signs appearing in from four to twenty-four hours. In scrofulous 
children small, raised follicular swellings commonly appear around the 
central specific area, the so-called scrofulous reaction. It should be 
remembered that a second injection of tuberculin in the same area on 
the same arm following an initial negative reaction may be positive. 
This is not an indication of infection, however; it is rather a mani- 
festation of local sensitization.^ 
(c) The Percutaneovs Test (il/oro).-— Moro has modified the vow 
Pirquet test in such a manner as to exclude the traumatism incidental 
to scarification. This is accomplished by rubbing into the skin of the 
abdomen or the chest an ointment made of 5 cc. of old tuberculin 
mixed intimately in 5 gm. of anhydrous lanolin. In practice a bit 
of the ointment 0.5 cm. in diameter is rubbed over an area of about 4 
square inches for about one-half minute. The ointment is left on the 
skin to absorb gradually. A positive reaction consists in the develop- 
ment, usually within twenty-four to forty-eight hours, of a number of 
small red papules within the area of inunction. Ordinarily but a few 
papules are formed ; less commonly a considerable crop appear. Rarely 
the skin in the immediate area is reddened and there may be slight 
itching. The papules are few in niunber in a mild reaction, usually 
from 2 to 8 or 10; they are red and from 1 to 2.5 mm. in diameter. A 
moderate reaction is characterized by many red papules, from 10 tf) 
100, which are rather closely crowded together and usually from 0.25 
to 2.5 mm. in diameter. The interpapular areas of skin may or may 
not be reddened. If the skin is reddened it frequently itches some- 
what. In a severe reaction papules appear within a few hours after 
inunction, many in number with a markedly hyperemic background. 
Itching is a very disagreeable feature of a severe reaction. 
{(I) The Detre Test. -~}iuma,n tuberculin is rubbed into one arm 
and bovine tuberculin is rubbed into the other, using preferably the 
cutaneous reaction of von Pirquet. It was supposed by Detre that 
the tuberculin reaction elicited will indicate the type of infection, 
whether it be of the bovine or the human bacillus. This test is not 
used as a routine by most clinicians. 
(e) The Ophthalmo Reactmi of Calmette? —Owe drop of a 1 per cent 
dilution of old tuberculin, previously purified by precipitation with 
alcohol, is instilled into the conjunctival sac. In tuberculous subjects 
this instillation is followed by a reddening of the caruncle and usually 
the conjunctiva as well. The reaction varies in intensity from a very 
mild local reddening of the caruncle to a conjunctivitis. The reaction 
becomes visible usually in from four to eight hours. The maximum 
1 The von Pirquet reaction is usually negative in tuberculous children during the 
acute stage of measles and occasionally in whooping cough. 
2 Munchen. med. Wchnschr., 1908, 55, 216. 
3 Compt. rend. Acad. Sci., 1907, vol. 144. Wolff-Eisner: Beitr. z. Klin. d. Tuberku- 
lose, 1907, 9, Heft 1. 
