By 1h Johnston: Leprosy 869 
of acid-fast bacilli in nasal mucus should not be regarded as 
diagnostic of leprosy in the absence of clinical signs. 
The diagnosis of leprosy may be considered under clinical and 
microscopical heads. 
CLINICAL 
The patient should be in a good light, and at first the examiner 
should stand some distance away, as by so doing he will often be 
able to distinguish certain areas which in the dark-skinned races 
show up only at a distance, such as dusky reddish patches, 
which on a near view one cannot differentiate at all from the 
surrounding skin. Fixing these patches in mind, they should 
next be palpated; usually a certain degree of inelasticity will be 
felt. Such a patch is less than an induration and is apparently 
not due to any subcutaneous cedema or effusion, but rather to an 
atrophy of muscular tissue. In old cases the skin will remain 
after being pinched up. In early cases these areas are excép- 
tionally greasy, but later on dry, and frequently they do not 
sweat. Tests for anesthesia should always be made in these 
spots. The center of the area is usually more anesthetic than 
the borders. One should also look for loss of eyebrows, nodules 
in the ears—or, in old people, for elongation of the pinna—and 
nodules in the nasal ale. In leprous skin lesions there does not 
seem to be a true pigmentation, as what is often called pigmenta- 
tion is really a loss of natural color as compared with the 
surrounding area. The most confusing diseases which are fre- 
quently mistaken for leprosy are syphilis, lupus, yaws, mycosis 
fungoides and psoriasis, elephantiasis, and madura foot. Some 
authors have cited syringomyelia as being especially difficult of 
differentiation. In a personal experience covering several thou- 
sand cases I have never seen a case of this disease. 
MICROSCOPICAL 
Success in detecting the leprosy bacillus depends largely on 
the method of taking the specimen. Selecting a nodule or the 
edge of an indurated area previously circumscribed with a 
sharp scalpel, one or more slight incisions should be made just 
through the true skin. If the incision is properly made, only 
a small amount of blood will appear. This is wiped off, and the 
serum which exudes is taken up by the blade of the scalpel; 
it is well to scrape the edges of the incision. The whole 
should be smeared as evenly and thinly as possible on a slide. 
Dry in air and fix by direct heating over the flame or by dropping 
one or two drops of alcohol on the slide and setting fire to it. 
