Cowpox was long observed by English country folk to be a preventive of smallpox. It was in hearing a servant woman say so that Dr. Jenner was drawn to the study which ended in his successful vaccinations, in all the triumphs since won in this department of medical science. For two thousand years the peasants of Italy have suspected mosquitoes and other insects to be concerned in the spread of malarial and other fevers. It remained for Dr. Ronald Ross in our day to prove that the suspicion was founded in truth. In “The Naturalist in La Plata,” one of the best books on natural history ever written, Mr. W. H. Hudson says:--“The country people in South America believe that the milky secretion exuded by the toad possesses wonderful curative properties; it is their invariable specific for shingles--a painful, dangerous malady common amongst them, and to cure it living toads are applied to the inflamed part. I dare say learned physicians would laugh at this cure, but then, if I mistake not, the learned have in past times laughed at other specifics used by the vulgar, but which now have honorable places in the pharmacopœia--pepsine, for example. More than two centuries ago, very ancient times for South America, the gauchos were accustomed to take the lining of the rhea’s (a large ostrich’s) stomach, dried and powdered, for ailments caused by impaired digestion; and the remedy is popular still. Science has gone over to them, and the ostrich-hunter now makes a double profit, one from the feathers, and the other from the dried stomachs which he supplies to the chemists of Buenos Ayres. Yet he was formerly told that to take the stomach of the ostrich to improve his digestion was as wild an idea as it would be to swallow birds’ feathers in order to fly.” Snake poison has long been used by the Hottentots as an antidote to snake poison. With aid from the Carnegie Institution of Washington, Dr. Hideyo Noguchi, of the University of Pennsylvania, has succeeded in producing antivenins, to use the medical term, for the venoms of the water-moccasin and _Crotalus adamanteus_ snakes, using the venoms themselves in preparing his antidotes. He is continuing his researches in this remarkable field of the healing art.