In many cases the immunity conferred by the first effectual vaccination would remain through life, and the subsequent vaccinations would produce no effect. In many other cases, however, the second or third vaccinations would take effect and produce a partial or complete vac cine-sore, thereby showing that the im munity conferred by the first had been more or less impaired and the person again susceptible to variola, but ally in the mild form called varioloid. By the regular repetition of vaccination at or near the times just indicated, the gradual loss of immunity known to take place in many cases after one vaccination is detected and remedied; and the trouble and expense occasioned thereby is so trifling compared with the impor tance of the object to be accomplished that no person is excusable for neglect ing it.
A new bacillus found in vaccine pust ules. It is present in the epithelial cells of the "vaccine-pulp" of calves, either as a rod-shaped form staining in a bipolar fashion or as a spherical or oval form taking the stain less perfectly. In the lymph from children, on the other hand, the rod form is not found, but large, round, refractive organisms are present similar to those found in calf-lymph which are looked upon as variation forms of the bacillus. Pure cultures of the bacillus were obtained on agar plates both from the calf-lymph and from lymph drawn from seven-day-old vesicles on the arms of children. These are iden tical with the bodies described by Guianieri and Pfeiffer in the corneal tis sue inoculated with vaccine-lymph and in the corneal vesicles in variola, and which were considered by them to be probably protozoa. By inoculation of
cultures of the bacillus into the arms of ' several children, a student, and himself, the author was successful in producing typical vesicles. Two other students gave no reaction; possibly they were im mune. Xakanishi (Centralb. f. Bakt., B. 27, No. 18, 1900).
Varioloid.—Within a few years after the general resort to cow-pox vaccina tion for preventing variola, experience showed that, in a small percentage of . those apparently well vaccinated, the immunity to variola was not complete. Such when exposed to the virus or con tagium of variola took that disease, but it passed through all its stages in a modi fied or mild form. Others whose vacci nation rendered them wholly immune for six or seven years subsequently came susceptible, generally to the mild form, though in some cases, in which the vaccination was practiced in infancy and not repeated, exposure to variola after the middle period of life has caused severe and even fatal cases of the latter disease. The cases occurring after cination are designated varioloid. They are caused solely by variola contagium, and are capable of communicating that disease in all its forms to any other persons not previously fully protected. Consequently they should be carefully isolated and treated in all respects the same as unmodified cases of the mild or discrete variety of variola; and the same vigilance in their cleansing should be exercised during their convalescence.