Report of experiments now being pursued in the Bacteriological Laboratory of the Academy / by Samuel G. Dixon.

  • Dixon, Samuel Gibson, 1851-1918.
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: Report of experiments now being pursued in the Bacteriological Laboratory of the Academy / by Samuel G. Dixon. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    MAY 91 REPORT Or EXPER.MENT^HOW BEING ^V*0*™* BACTER.O- LOGICAL LAB^RA^ORY OF^ACADEMY. BY SAMu\il*Jl»rjU^rM. D. Experiments show that the twenty-fifth and the second growth> of the tubercle bacillus will multiply with great rapidity when planted on a nutrient medium made up of:— Extract of Beef 25-g AqrDist: 700-CC Dry peptone Agar-agar S Chlor. Soda 5S Dist. Water (added.) B0G-CC Glycerine 1<>0.<W The turbidity is removed by the slow mixing ot the whites ot two hens eggs. If four distinct needle tracks are made with these bacilli length- wise in a half-inch tube containing this medium, the entire surface will be covered with a thin layer of tuberculous growth within five weeks. The bacilli from the twenty-fifth culture present a variety of forms, some club-shaped, others branched, while many would appear to grow to a great length, certainly measuring in some in- stances three times that of the average tubercle bacillus described by the authorities on this organism. To obtain the toxic substance of bacilli, they may be floated in a liquid medium. By this method we can filter out the toxic sub- stance without submitting the medium to heat. With some of the toxic agents generated by aerobic micro-organisms, this method will prove of vital importance, as heat destroys many of the ptomaines. The tuberculous poison is most readily and cheaply obtained from tuberculous lungs of cows and the viscera of other animals. Before giving a resume of the simple method of obtaining the toxic- agent from the lungs, I wish to thank Dr. Francis Bridge, State Veterinary Inspector, for his kindness in furnishing the-Laboratorv with tuberculous material. It is owing to his courteous attention that I have never wanted for tuberculous lungs of cows since 1889. He has supplied the numerous demands at the shortest possible notice, and has insisted upon contributing his time and trouble for the benefit of science.