The microscope : its history, construction, and application, being a familiar introduction to the use of the instrument, and the study of microscopical science / by Jabez Hogg.

  • Hogg, Jabez, 1817-1899.
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: The microscope : its history, construction, and application, being a familiar introduction to the use of the instrument, and the study of microscopical science / by Jabez Hogg. Source: Wellcome Collection.

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

    362/780 (page 328)
    Ill this way colonies are formed, each possessing its own biological characteristics and morphological appearances (Fig. 260). To maintain individuals isolated from each other during growth, and free from contamination, it is only necessary to thin out the cultivation to protect the plates from the air, and to have facilities for examining them from time to time, and observing the charac- teristic microscopical appearances. The colonies on nutrient gelatine examined with a low power (Fig. 260), if micro-organisms such &s Bacillus anthraces and Proteus mirahilis, the naked eye appearances in test-tubes of the growth of the bacilli of anthrax and tubercle, and the brilliant growth of micro-coccus prodigiosus, may be given as examples in which the appearances are often very striking and sometimes quite characteristic. I must, however, first direct attention to a well-recognised fact, that bacteriology only touches animal pathology at a few points, and that so far from bacteria being synonymous with disease germs, the majority of these remarkable organisms appear to be beneficent rather than inimical to man. This is of immense importance to science, as I shall attempt to show further on; although even a brief description of all the useful ferments due to bacteria and brought into use would occupy a volume to themselves, and call for a school of bacteriology quite apart from that involved in the medical aspect of the question, for the purpose of fully investigating problems raised by the agricul- turist, the forester, the gardener, the dairyman, brewer, dyer, tanner, and other industries, which open up vistas of practical application, and to some extent are already being taken advantage of in commerce. The Preparation of Nutrient Gelatine and Agar-agar.—Take half a kilogramme (one pound) of beef as free as possible from fat, chop finely, transfer to a flask or cylindrical vessel, and shake up well with a litre of distilled water. Place the vessel in an ice-pail, or ice-cupboard, or in winter in a cold cellar, and leave for the night. Next morning commence with the preparation of all requisite apparatus. Thoroughly wash and rinse with alcohol about 100 test-tubes, and allow them to dry. Plug the mouths of the test- tubes with cotton-wool, place them in their wire cages in the hot-air steriliser, to be heated for an hour at a temperature of 150° C. In the same manner cleanse and sterilise several flasks, and a small