Physalix working in Chauveau’s laboratory has found the best results from the use of weakened artificial cultures. He cultivated the microbe of Lignieres in peptonised bouillon having 6 per cent. of glycerine, and allowed successive cultures to rest (without reseeding a new culture fluid), after they have attained to their full growth. The strength of the culture is in inverse ratio to the period that elapsed between successive cultures, leading up to this one, and the first inoculation is made with the weakest product that will produce a very limited local swelling which is fully developed in 48 hours, and disappears in a few days. Three or four inoculations are made successively with cultures of gradually encreasing potency, after which immunity persists for years. It is to be understood, that an overdose will overcome the immunity at any time; also that the passage of a culture of lessened potency through a dog or Guinea pig will raise it to its original virulence. Physalix operated only on young dogs, that had not shed their milk teeth, and injected 2 to 3 c.c. of the culture as a dose with only 2.5% mortality. Others had less success. _Treatment._ To secure good results in the treatment of distemper every attention must be paid to good hygiene. An open air life in summer, and a roomy, clean, well-aired, warmed building in winter are most important. Chills, foul air, and filth generally are to be carefully guarded against. Food should be moderate in amount, easily digested and nutritious. Milk is especially good (sweet, skim or buttermilk); then biscuit and milk, or in patients accustomed to animal food, lean meat, minced, scraped or pulped. Warm baths are often advantageous, but they must be given with great caution to avoid chill. Medicinal treatment is largely symptomatic. An excessively high temperature (104° and upward) may be met by warm baths, or antipyretics—quinine, acetanilid, salicylate of soda, antipyrine, phenacetin, or even damp compresses to the sides. As a rule, however, it is not well to continue such agents as acetanilid, antipyrine or phenacetin longer than is absolutely needful to reduce excessive temperature.