Interim report of the Royal Commission appointed to enquire into the relations of human and animal tuberculosis; and : Second interim report of the Royal Commission appointed to enquire into the relations of human and animal tuberculosis.
- Great Britain. Royal Commission on Tuberculosis (Human and Bovine)
- Date:
- 1904 [and] 1907
Licence: In copyright
Credit: Interim report of the Royal Commission appointed to enquire into the relations of human and animal tuberculosis; and : Second interim report of the Royal Commission appointed to enquire into the relations of human and animal tuberculosis. 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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![presented the characters of a bacillus of bovine tuberculosis highly dysgonic and very virulent. We have attempted to repeat these passage experiments, making use of two of the three cases described above and also of four cases from Group II., but beginning with a culture not an emulsion. The result was in each case negative ; but in none of them can the experiment, for one reason or other, as- may be seen from the details given in the Appendix, be regarded as adequately parallel to the three experiments in question. We have also carried out passage experiments with rabbits, passing the material of eleven cases (one of them H. 16 J.H.) intravenously or intraperitone- al] y through the bodies of rabbits, making two, three, or four or even more passages in each case. So far the results have been negative. The negative result obtained in all the above experiments, even admitting that they were not wholly satisfactory, at least shows that the change in the characters and properties of the bacillus witnessed in the three passage experi- ments under discussion is not an invariable result of passage. We may safely assume that in the three experiments in question certain special conditions were present, and these special conditions determined that during the passage the initial eugonic bacillus of low virulence was in some way or other replaced by the final dysgonic bacillus of high virulence. Instability. 58. Before proceeding further it will bo convenient to mike a brief statement of certain results bearing on the stability of the tubercle bacillus which we have met with in the course of our investigations. We find that the cultural characters are not absolutely stable. Dysgonic bacilli which grow with difficulty on glycerin serum or glycerin broth may by repeated sub-culturing on such a medium be finally induced to grow with ease upon it. The bacilli of Grade III., whether of bovine or human source, have been observed by Dr. Eastwood to be irregular and uncertain in their growth on glycerin media; samples taken from the same culture on serum Avill grow on glycerin broth and other glycerin media in different ways, presenting different kinds of growth. In respect to stability in virulence which is not necessarily affected by cultivation, for we have repeatedly kept a strain for a long time (in one instance three years) in cultivation without any lessening of virulence, the following results deserve attention : — In H. 16, J.H., one of the passage experiments, an emulsion from the greatly diseased prescapular gland of Calf 273, affected with a generalised though not fatal tuberculosis, proved to be highly virulent, producing fatal generalised progressive tuberculosis in the calf and in the rabbit. Yet a culture from this gland, after having been sub-cultured for six generations, being ten months old, did not possess the virulence indicated by the emulsion ; it exhibited the low virulence of Group II., and moreover was very eugonic, being placed in Grade V., side by side with a culture from Calf 157, injected with the original material. In H. 13, A.D., also a passage experiment, the long thoracic lymphatic gland of Calf 301, affected with a fatal generalised progressive tuberculosis, gave a highly virulent emulsion, causing fatal generalised progressive tuberculosis in the calf and the rabbit. Yet a culture from this gland injected in a close of 50 mgrs. failed to produce this result; it had not the virulence of the emulsion, and moreover, when examined in the third sub-culture was found to be moderately eugonic, being placed in Grade IV. Again in the first feeding experiment, H. 2, Sp. A., the emulsion from the affected glands of Heifer 13 did not always show the same virulence. Injected into Calf 111, it gave rise only to an exceedingly limited retrogressive tuberculosis, and a culture obtained through a guinea- pig from the affected organs of this calf also possessed a very low virulence. Yet the same emulsion passed through a guinea-pig (the effect of which, us we have seen again and again, is only to increase the number of bacilli, not in any way to change their character) and injected into Calf 153 produced a fatal generalised progressive tuberculosis, so severe that it](https://iiif.wellcomecollection.org/image/b21366366_0047.jp2/full/800%2C/0/default.jpg)
