Applied bacteriology; an introductory handbook for the use of students, medical officers of health, analysts and sanitarians / by T.H. Pearmain and C.G. Moor.

  • Moor, C. G. (Cresacre George)
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: Applied bacteriology; an introductory handbook for the use of students, medical officers of health, analysts and sanitarians / by T.H. Pearmain and C.G. Moor. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    and distributed by means of a sterile wire over the surface, care being taken not to bring the gelatine too near the edge. The glass cover is then lowered, and other plates can then be prepared in the same way by placing them on a metal or glass rack over the first plate. Petri’s Dishes.—The use of these has some advantages over the plate method of Koch. The dishes are from 10 to 20 centimetres wide and about 1‘5 or 2 centimetres deep. Fig. 14.—PeTiu Double Dish. and have roughly-fitting covers of the same form as the dishes themselves. These dishes can be safely carried about, and do not need the levelling apparatus ; moreover, the colonies may be examined and counted if desired with- out removing the lid, and, consequently, without the exposure to contamination to w'hich Koch’s form of plate is liable. Petri’s double dishes are made both in the round and square form. Esmarch’s Holl Cultures.—A useful modification of Koch’s method is that of Von Esmarch. Instead of pouring the liquid gelatine medium upon plates or in shallow dishes, it is distributed in a thin layer upon the walls of a wide test- tube. This is done by rotating the tube upon a block of ice or in iced water. It is more convenient to turn the tubes upon a block of ice having a horizontal surface, in which a shallow grove is first made by means of a test-tube containing hot water. In the winter the tube can be re- volved under the water service tap to solidify the jelly. A little practice will enable the operator to distribute the jelly in an even layer on the walls of the tube, and as