toxin. A febrile reaction of more than 1.5° C. following the injection is said to be specific of the disease. Babes has asserted that the injection of this toxic product into susceptible animals will protect them from the disease.

Various experiments have been made with curative objects in view. Certain observers claim to have seen. good results follow the injection of mallein in repeated small doses. Others, as Chenot and Picq, find the bloodserum from immune animals like the ox to be curative when injected into infected guinea-pigs.

CHAPTER IV.

SYPHILIS.

ALTHOUGH Syphilis is almost as well known as it is widespread, we have not yet discovered for it a definite specific cause. Whether it is due to a protozoan parasite, or whether it is due to a bacterium, the future must decide. Numerous claims have been made by those whose studies have revealed organisms of one kind or another in syphilitic tissues, but no one has yet succeeded either in isolating, cultivating, or successfully inoculating them.

In 1884 and 1885, Lustgarten published a method for the staining of bacilli which he had found in syphilitic tissues and assumed to be the cause of the disease. The staining, which is very complicated, requires that the sections of tissue be stained in Ehrlich's anilin-water gentian-violet solution for twelve to twenty-four hours at the temperature of the room, or for two hours at 40° C.; washed for a few minutes in absolute alcohol; then immersed for about ten seconds in a 11⁄2 per cent. permanganate-of-potassium solution, after which they are placed in an aqueous solution of sulphurous acid for one to two seconds, thoroughly washed in water, run through alcohol and oil of cloves, and finally mounted in Canada balsam dissolved in xylol.

If the bacilli are supposed to be present in pus or discharges from syphilitic lesions, the cover-glasses spread with the material are stained in the same manner, except that for the first washing distilled water instead of absolute alcohol is used.

This method undergoes a modification in the hands of De Giacomi, who prefers to stain the cover-glasses in hot

anilin-water-fuchsin solution for a few moments, sections. in the same solution cold for twenty-four hours; then immerse them first in a weak, then in a strong, solution of chlorid of iron. The cover-glasses are washed in water, sections in alcohol, and subsequently passed through the usual reagents for dehydration and clearing.

FIG. 60.-Bacillus of syphilis (Lustgarten), from a condyloma; x 1000 (Itzerott and Niemann).

In some syphilitic tissues these methods suffice to define distinct bacilli with a remarkable similarity to the tubercle bacillus. The organism is about the same size as, and even more frequently curved than, the tubercle bacillus, but often presents a club-like enlargement of one end (involution-form?). The bacilli very frequently occur singly, though more often in groups, and never lie free, but are always enclosed in cells. These bacilli are not always found in syphilitic lesions, nor is their demonstration easy under the most favorable circumstances. Lustgarten emphasizes particularly that they are only demonstrable after the most painstaking technical procedures.

The probability of the specificity of this organism was considerably lessened by the observation by Matterstock, Travel, and Alvarez that in preputial smegma, and also

in vulvar smegma from healthy individuals, a similar organism, identical both in morphology and staining peculiarities, could be demonstrated. Of course the occurrence of Lustgarten's bacillus in the internal organs could not but argue against the probability of its identity with the smegma bacillus ; but Lustgarten himself pointed out that the bacilli of both tuberculosis and leprosy stain by his method, and thus gave Baumgarten the right to suggest that the few cases well adapted for the demonstration of the Lustgarten bacilli might be cases of mixed infection of tuberculosis and syphilis.

The bacillus has not been isolated or cultivated, and its proper relation to syphilis is a matter which must be decided by future experimentation.

CHAPTER V.

ACTINOMYCOSIS.

IN 1845, Langenbeck discovered that the specific disease of cattle known as actinomycosis could be communicated to man. His observations, however, were not given to the world until 1878, one year after Bollinger had discovered the cause of the disease in animals.

Actinomycosis is a disease almost peculiar to the bovine animals, though sometimes occurring in hogs, horses, men, and other animals.

The first manifestations of the disease are usually found either about the jaw or in the tongue, in either of which