The essentials of practical bacteriology : an elementary laboratory book for students and practitioners / by H. J. Curtis.

  • Curtis, Henry J.
Date:
1900
Catalogue details

Licence: In copyright

Credit: The essentials of practical bacteriology : an elementary laboratory book for students and practitioners / by H. J. Curtis. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    by B. typhosus, &c., the methods referred to, in the special chapters deahng witli those organisms, should be employed. The purity of water.—Various ' standards of purity' have been proposed, and for an account of these the reader is referred to works on Hygiene.' Pure water, according to Miquel's standard, may contain from 100 to 1,000 organisms per c.c, very impure watsr being defined to contain 100,000, and upwards, per c.c. Filtra- tion to be considered effective, according to Frankland, should remove practically all organisms. Soil A loopful of earth from any specific source may be evenly diffused through a tube of hquefied gelatine; and, from this, gelatine plates and roll-tubes of various dilutions made. Subcultures from the different colonies appearing may be made, to isolate the various aerobes, and anaerobes present. Stab-glucose gelatine and glucose- agar cultures should be made. For the isolation of tetanus baciUi, the special method of fractional separation, mentioned on p. 226, may be employed. If necessary, an animal may be inoculated, and the tetanus bacillus isolated from it. MUk Milk.—For the examination of milk supposed to be contaminated with organisms, various methods may be adopted, according to tho nature of the contagion. In the case of an epidemic of typhoid fever, supposed to be due to infection of the milk, plates of gelatine, potato-gelatine, and agar-agar may be made in the usual way; and a quantitative examination may be similarly carried out, using 0*1, 0'25, 0'5 c.c. respectively of milk for separate plates. In the case of tuberculosis, it is best to centrifugalise the milk. The supernatant fluid whey being poured off, the thicker deposit is made into film preparations and examined for B. tuberculosis, by the usual methods, Ziehl-Neelsen's being the best. After fixing, and before proceeding to stain the film, it is sometimes useful to clarify it by means of ether, which removes excessive fat. ]'n the case of diphtheria, the Klebs-Loflfler bacilli may be found on centrifugalising the milk and examining the deposit at the bottom of the tube. In this connection, it may be useful to note that epidemics of acute ' For instance, Kenwood's Public Health Laboratory Work, p. 432,