Page:The Indian Journal of Medical Research, 1920.djvu/25

R. W. Fisher. 227 series of experiments, with the object of so improving on Green's original method, as to overcome its obvious shortcomings. He argued that the chloroform was probably left too long in contact with the lymph, thus endangering the vaccine virus. Therefore, after chloroform had been passed for 2 to 3 hours, air was bubbled through the lymph and all trace of chloroform removed. He found that the extraneous germs were killed off by this method, so that plates poured from the chloroformed lymph showed no growth of the usual flora found in the crude lymph. The lymph, on the other hand, proved quite active and gave excellent results in the hands of vaccinators. It was found possible, by using this method, to have a pure lymph ready for issue in two weeks from the time of collection of the pulp from the calf, so that prolonged storage was unnecessary for purification purposes. Modifications of the process have been introduced in the light of experience and the objections, which were valid against the original method of Green, have been entirely overcome. The results obtained, with our chloroformed vaccine lymph in a tropical country, will bear comparison with those obtained in temperate climates, where more conservative methods of purification are still carried out. The method has stood the test of experience, and it is claimed that a vaccine lymph is issued from Belgaum, of a very high standard of potency, free from the usual flora of extraneous micro-organisms. Where sporebearing germs and moulds gain access to vaccine lymph, no known method will eradicate them which will not, at the same time, destroy the vital virus. But where proper care is taken in all the details of preparing the calves for vaccination, and collecting and handling the lymph, and sufficient staff is employed to enable this to be insisted upon, the introduction of these spore-bearing organisms can be reduced to a minimum, and, with the exception of tetanus, none of these resistent germs are found to have any pathogenic effect. Harvey 1 has stated that, with care, pathogenic organisms, such as those of tetanus and malignant oedema, can be absolutely excluded from the lymph, and Dr. Anderson, 8 Director of the Hygienic Laboratory, U. S. A., Public Health Service, records that vaccine for 2,000,000 persons has passed through the Laboratory and in no case has the organism of tetanus been detected, although specially searched for ; and he further states that ' Where tetanus occurs after vaccination, the infection is received by a contamination of the vaccination wound such as may occur in the infection of any other surgical wound not properly cared for.'