Volume 1
Final report of the Royal Commission appointed to inquire into the relations of human and animal tuberculosis. Part II. Appendix. : 1.- Certain human viruses of irregular type. 2.- The excretion of tubercle bacilli in the milk of animals. 3.- Swine tuberculosis. 4.- Immunity.
- Great Britain. Royal Commission on Tuberculosis (Human and Bovine)
- Date:
- 1904-1913
Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Credit: Final report of the Royal Commission appointed to inquire into the relations of human and animal tuberculosis. Part II. Appendix. : 1.- Certain human viruses of irregular type. 2.- The excretion of tubercle bacilli in the milk of animals. 3.- Swine tuberculosis. 4.- Immunity. Source: Wellcome Collection.
Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.
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![This report gives an account of the attempts made to change the human tubercle bacillus into the bovine tubercle bacillus by passage through the bodies of bovines. It gives in addition the results of passage experiments through the rabbit and rat and of the investigation of cultures recovered from various species of animals after a single residence of long duration. The experiments are grouped together according to the species of animal used. The experiments with calves are the most numerous and the most important and are described first. The Passage Experiments.—Six strains of tubercle bacilli with the properties of the human tubercle bacillus have been passed each through one or more series of calves in succession. In three of the six experiments the virus was inoculated in the beginning into two calves, from each of which the virus was continued through a separate series of animals ; in other instances the virus after passing through a single line of calves was sent towards the end of the experiment through a double series. In two of the six experiments the passage was begun with emulsions of human tuberculous tissues, in three with culture, and in one with culture for two series and tissue emulsion for a third. In each case the passage was continued with emulsions of tuberculous tissues taken from the preceding calf, or from guinea-pigs inoculated with the calf lesions. Experience here has shown that when a virus containing human tubercle bacilli only is passed every three or four months from one calf to another in emulsions of tuberculous tissues from the preceding animal, the bacilli gradually die out and the experiment cannot be carried further than the third calf on account of lack of tuberculous material and paucity of bacilli. In these circumstances, if the passage is to be continued, resort must be had to some method of increasing the numbers of the bacilli. This increase can be secured by isolating a culture or by passing the virus through the body of a susceptible animal such as the guinea-pig in which the bacilli are able to multiply rapidly. Of the two methods I chose the second, because it seemed to me that continuous contact with animal tissues would be more likely to preserve slight variations in the direction of increased virulence than if the bacilli were made to live a saprophytic existence between the passage animals. All the guinea-pigs used were young animals bred on the quarantine side of the farm, well removed from all sources of infection. The calves were Jersej's from one and a half to six months old, and had not reacted to the tuberculin test. Special precautions have been taken to guard against the introduction into the passage animals of virulent bacilli from other experimental animals. All the animals in connection with two of the most prolonged and extensive experiments (with Viruses H. 80. D M. and H. 81. P.W.) had a special attendant and lived in sheds, situated on a distant part of the farm, which had never been used for animals infected with virulent bacilli, and the animals in the other experiments, though living on the experimental side of the farm were carefully isolated from other infected animals. In the case of each virus the virulence of the culture isolated from the original material was tested on a calf or calves and on rabbits, and the cultural characters on artificial media were determined. In those cases in which the experiment began with emulsions of tuberculous tissues, rabbits as well as calves were inoculated to- test the virulence of the material used. The plan of investigation was the same in each experiment ; a culture was isolated from every calf and tested on artificial media to see whether there had been any change in the cultural characters of the bacillus ; occasionally these cultures were tested on rabbits, but the majority were held in reserve to act as controls should tiie results in the succeeding calves point to an increase of virulence ; when- ever a calf was inoculated one or two rabbits were inoculated at the same time with some of the same material. [In the following abstracts the results of these inocula- tions into rabbits are not always referred to ; they were in every case in agreement with the results in the calves.] The guinea-pigs used to increase the numbers of the bacilli were all inoculated intraperitoneally. Tuberculous tissues used in the preparation of the emulsions](https://iiif.wellcomecollection.org/image/b2135327x_0001_0064.jp2/full/800%2C/0/default.jpg)
