Volume 4

Final report of the Royal Commission appointed to inquire into the relations of human and animal tuberculosis.

  • Great Britain. Royal Commission on Tuberculosis
Date:
1911
Catalogue details

Licence: Public Domain Mark

Credit: Final report of the Royal Commission appointed to inquire into the relations of human and animal tuberculosis. Source: Wellcome Collection.

    13/362 (page 11)
    RESULTS OF REINVESTIGATION. Four strains of the virus were in existence, two from the original material which had been separately subcultivated, and those from Calves 787 and 797. All four strains were tested on rabbits and two on calves. Virulence Tests—The culture derived from the original material which had been cultivated by Cobbett in the Blythwood laboratory was tested after 203 months’ cultivation (21st generation). Six rabbits were inoculated, two intravenously, two intraperitoneally, and two subcutaneously. One died of pseudo-tuberculosis in 11 days ; the others were all killed after 130 days and showed slight tuberculosis of a chronic type. Later on a culture of the 25th generation was inoculated subcutaneously into two calves (Calf 1191 and Calf 1193) and two rabbits (doses 50 and 100 mg.) ; the calves after 94 and 99 days had only slight retrogressive tuberculosis, and each of the rabbits after 142 days had a local lesion only. The culture from the original material had been given shortly after its isolation to Dr. Eastwood, and had been subcultivated regularly on serum ever since at the Royalcot Jaboratory ; in order to ascertain whether this strain had also Jost its virulence, I obtained a culture from him and inoculated it into a series of three rabbits ; the culture had then been 224 months in cultivation and was the 25th generation. Two of the rabbits were inoculated intravenously and one intraperitoneally ; the former died of general tuberculosis in 16 and 31 days respectively ; the latter was killed after 163 days and showed chronic general tuberculosis, the injection having been partly intracoecal ; the type of disease produced in the three cases was identical with that produced by a bovine tubercle bacillus. The culture derived from Calf 787 was tested after 16 months’ artificial cultivation. Six rabbits were inoculated, two intravenously, two intraperitoneally, and two subcutaneously. All died of general tuberculosis in from 14 to 90 days. The culture derived from Calf 797 was also tested after 16 months’ artificial cultivation. Six rabbits were inoculated, two intravenously, two intraperitoneally, and two subcutaneously. One intraperitoneal animal died in 12 days of acute tuberculosis, complicated with severe psorospermosis of the liver ; the others all died of general tuberculosis in from 13 to 80 days. Cultural Characters.—The Blythwood strain of the original culture and a strain from each of the two calves inoculated with it (Nos. 1191 and 1193) grew well on glycerin media, as did also the Royalcot strain. The two strains from Calf 787 and 797 did not grow so well as the strains from the original material, and resembled the more easy growing strains of bovine origin. Summary.—The Blythwood strain of the original culture exhibited the cultural characters and virulence of a human tubercle bacillus: the Royalcot strain had the cultural characters of a human tubercle bacillus but resembled a bovine tubercle bacillus in virulence ; the strains derived from Calves 787 and 797 were identical with bovine tubercle bacilli. SUMMARY OF PRELIMINARY EXPERIMENTS. Ten strains from the four viruses (H 13.“ A.D.”, H 16.“J.H.”, H 17.“ Sp.B.”, and H 49.“ T.C.”), which during passage through the animal body underwent a change of character have been retested as to their cultural characters and virulence for rabbits. Two strains from the virus designated H 2.“Sp.A.”, the original material of which was mixed sputum have also been retested [this virus was passed through a series of animals, and from some a slightly virulent, from others a virulent culture was isolated ]. With two exceptions the cultural characters and the virulence of the twelve ‘strains were found strictly in accordance ; those strains which grew well on culture media had low virulence for rabbits, those which grew with difficulty were highly virulent for rabbits. The preliminary tests therefore gave no indication of the presence in any of these ten strains of two different kinds of organisms, and no further investi- gations with them were carried out. Whatever they had been they were now stable. The first exception was the culture isolated from the mediastinal gland of Calf 301 (Virus H 13. A.D.”), an animal which died of general tuberculosis after the subcutaneous inoculation (in passage) of an emulsion from the tuberculous organs of guinea-pigs ; the culture was eugonic, and when tested by Dr. Cobbett after 15 months artificial cultivation produced in two rabbits slight chronic general tuber- culosis, and in two calves inoculated with 50 milligrammes subcutaneously limited tuberculosis in one, and slight general tuberculosis in the other. When retested by me after a period of three years’ artificial cultivation it grew luxuriantly on glycerin media, and produced in two calves generalised tuberculosis, not severe and not -apparently progressive, and fatal general progressive tuberculosis in rabbits. It was more virulent therefore than when tested by Dr. Cobbett, but less virulent than a ‘bovine tubercle bacillus. The second exception was the culture derived directly from the mesenteric glands of a youth aged 18 (Virus H 49.“ 'T.C.”). This culture had been cultivated in two different laboratories, in the Blythwood laboratory in charge of Dr. Cobbett and, ‘since an early generation, in the Royalcot laboratory in charge of Dr. Eastwood. The former, called the Blythwood strain, had been tested by Dr. Cobbett two and seven months after isolation, and produced in calves and rabbits fatal general progressive tuberculosis ; it was again tested 134 months after its isolation and was found to have lost its virulence. The latter, or Royalcot strain, was tested by me when it had been in cultivation about two years, and was found to be virulent for the calf and rabbit, though not so virulent as a bovine tubercle bacillus. Both of the strains grew luxuriantly on artificial media, and were in this respect identical. With these two exceptional strains further experiments were made (vide infra),