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"I am referring to these experiments only as an illustration that it is through the experimental side of medicine, the experimental spirit in medicine, that these great revolutions have been effected, revolutions with which there is nothing else in human endeavour to compare, from the standpoint of humanity. There is not anything else in the whole development of the British nation that is


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This chart shows the occurrence of yellow fever in Havana for the epidemic year, March 1, 1901, to March 1, 1902, during which year the disease was fought on the mosquito theory. The continuous line gives the number of cases; the dotted line gives the mortality. (From Dr. Kelly's "Life of Walter Reed.")

going to have so much importance as the discovery of the mode of the transmission of malaria. It is going to make the Tropics habitable. And all this has come about through the experimental method and the experimental spirit. Without these, such investigations could not have been made, and these perfectly phenomenal results could not have been achieved. It was the same spirit that gave us anesthesia, and the same spirit that has given us antiseptic



surgery, and the same spirit that has given us preventive medicine three things which stand out in the record of human achievement with which nothing else may be compared-I mean from the standpoint of everyday, common humanity. This experimental investigation into the interaction between the mosquito and man producing yellow fever would never have been thought of, if it had not been for previous experiments on animals. The men who made these investigations spent their lives in laboratories, and their whole work has been based on experimentation on animals. They could not otherwise, of course, have ventured to devise a series of experiments of this sort."

NOTE. As one species of mosquito conveys yellow fever from man to man, so another species of mosquito conveys malaria from man to man. In the long series of observations on malaria, three facts are especially to be noted: (1) In 1898, in India, by experiments with mosquitoes and small birds, Ross discovered the germs of "birdmalaria" in the stomach of the mosquito, and was able to infect healthy birds by causing the infected mosquito to bite them; (2) In 1900, Sambon and Low and Terzi set up a mosquito-proof hut near Ostia, in a part of the Campagna that was saturated with malaria. They lived in this hut through the whole of the malaria season; they took not a grain of quinine, and they had no malaria. A similar experiment, on a large scale, was made by Grassi among the workmen and their families on the BattipagliaReggio railway. (3) In 1900, also, a consignment of mosquitoes, fed on a case of malaria in Rome, was sent to the London School of Tropical Medicine, and Dr. Manson, Sir Patrick Manson's son, and Dr. Warren submitted themselves to be bitten. They both developed the disease, and the germs were found in their blood.

The campaign against malaria and yellow fever, therefore, is a campaign against the mosquito, plus such measures as the segregation of the white man's houses from the native huts, the State-aided distribution of quinine, and the general use of mosquito netting, etc. The work of the "mosquito brigades" is to destroy or remove the haunts and breeding-places of the mosquito. It breeds in little collections of stagnant water, laying its eggs on the water ponds, swamps, puddles, roadside ditches, tanks, cisterns, and all such chance receptacles of rain-water as rain-barrels, pots and pans and broken bottles and old biscuit-tins-all the rubbish of the backyard. Pools and ditches are drained, or stocked with minnows, or filmed with kerosene to kill the larvæ; broken crockery and the like débris are carted away; cisterns and wells and rain-barrels are properly protected; everywhere the surface soil is tidied up, and all collections of stagnant water are removed, or are set running, or are covered over.

The President of the United States, in his address to the Philadelphia Medical Club, May 4, 1911, gave a full account of the results achieved against yellow fever in Havana, tropical anæmia in Porto Rico, cholera, small-pox, plague, malaria, leprosy, and beri-beri in the Philippines, yellow fever and malaria in the Panama Zone, and typhoid fever in Texas and California. This address will be issued in pamphlet form by the Research Defence Society.




MR. STEWART STOCKMAN, December 5 and 12, 1906

MR. STEWART STOCKMAN, M.R.C.V.S., Chief Veterinary Officer of the Board of Agriculture and Fisheries, formerly Principal Veterinary Surgeon in the Transvaal Agricultural Department, said that there were two kinds of contagious diseases in animals which caused serious illhealth and loss of life: these were the bacterial diseases, and the parasitic diseases. He pointed out that the parasitic diseases, such as tape-worms, had come to be understood by experiments on animals; and said that without that understanding, measures for prevention would have been impossible. In the same way the measures for preventing trichinosis in man were arrived at by experiments on animals. He went on to speak of the diagnosis of certain contagious diseases of animals, such as anthrax, glanders, tuberculosis, swine-fever, and swineerysipelas; sometimes this diagnosis was possible only by the help of inoculation experiments. He was then asked to state his experience of the action of preventive inoculation upon animal plagues. He answered, "The methods of inoculation have in every case been arrived at

and proved by experiments on animals, and most of the substances employed to produce immunity can only be prepared by inoculation experiments on animals."

With regard to rinderpest, he said that it had cost Great Britain, between 1865 and 1869, £1,119,994. "In 1897, the appearance of rinderpest in South Africa resulted in the disease being studied with a view to discovering a method of preventive inoculation. The investigations were successful, and the benefits obtained from anti-rinderpest serum are recognised in every country where the disease has appeared since the method was introduced. . . . After peace was declared in South Africa, rinderpest was one of the diseases against which the newly created Veterinary Department had to direct operations; and it was dealt with by the serum method. During the period in which I was Principal Veterinary Surgeon to the Transvaal Government, about 14 outbreaks were reported and stamped out in various parts of the Colony. . . The final outbreak I am able to give more particulars about, because it occurred at the time the country was very much more settled; it occurred in a large native location, where the sick and in-contact animals numbered about 800. By the use of the serum the disease was stamped out, in the last affected herd, in about a month. The death-rate was 10 per cent., whereas it may be from 50 per cent. to 100 per cent. from the disease alone; and, of course, there may be a very much larger death-rate, on account of animals which have to be slaughtered to prevent the further spread of the disease, when the rinderpest has to be dealt with in the absence of the inoculation method. . . . The discovery of the serum method has been an enormous boon to South Africa."


With regard to contagious pleuro-pneumonia, he pointed out that, from September 1890 to the end of 1898, when

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