Upon the intracellular constituents of the typhoid bacillus / by Allan Macfadyen and Sydney Rowland.

  • Macfayden, Allan, 1860-1907.
Date:
1903
Catalogue details

Licence: In copyright

Credit: Upon the intracellular constituents of the typhoid bacillus / by Allan Macfadyen and Sydney Rowland. 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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    continued until no entire micro-organisms are found on microscopical examination, a result which can be accomplished in from 1^2 to 2 hours, when dealing with 0.5 to 1 g of pasty organisms. It must be remembered that as the above sequence of operations will take place at about — 190 C., the contents of D are in the condition of a dry powder. As a result of this process, there is obtained a pasty mass (when thawed), consisting of the entire substance of the organisms used. Moreover, this substance, at the moment of thawing, is chemically identical with the living protoplasm of the cell, the whole disintegration having occurred under conditions which preclude the possibility of any chemical change taking place. This pasty mass is mixed with salt solution (0.75 p. c.), rubbed up in an agate mortar, and the opaque suspension thus obtained is centrifugal- ised until free from suspended matter, and an opalescent solution of the intracellular constituents of the organism results. The centrifugalisation of such minutely divided material is occas- sionally a matter of difficulty, more especially if, by chance any unground organisms are found in the suspension. In those cases, in which a sterile juice is required the centrifugalisation must be very vigorous, and for this purpose it has been found that the best results are given by a very simple form of centrifuge, consisting of a horizontally mounted steel disc (36 in- ches in diameter) on the periphery of which are mounted strong glass tubes in steel cases hung on trunnions, the disc making from 3,000 re- volutions per minute. The glass tubes to prevent fracture under the great strain are floated in mercury, contained in the covering steel tubes. With such a disc, sterile juices have been obtained. The centrifugalised celljuice was as a rule equivalent to a 10 per cent solution of the intracellular constituents obtained. It represented the intracellular constituents of the typhoid organisms soluble in physiological salt solution, after a complete disintegration of the cells had been accom- plished. It is this material which was used in the experiments we are about to describe and it consisted of a bacterial celljuice practically identical with that contained within the living cell. These juices likewise had the merit of possessing a constant con- stitution, and thus were capable of being standardised as regards their physiological action. V. Demonstration of intracellular toxin. The first experiments were carried out with the view of testing whether the typhoid celljuices obtained by cold grinding methods pos- sessed any toxic properties. It was found that if such a disintegrated mass be freed from whole bacilli (if present) and from other suspended in- soluble particles by centrifugalisation, an opalescent fluid results which on inoculation into animals in small doses, invariably proves toxic or fatal. It was therefore concluded that the typhoid bacillus contains within itself an intracellular toxin. The toxin thus obtained and employed for ex- periment is a ten per cent solution in normal saline of such intracellular constituents of the typhoid bacillus as are soluble in such a medium. The standard adopted in estimating the toxicity of the typhoid cell- juice was the amount found to prove fatal on intraperitoneal injection into the guinea pig. The intracellular fluid under these circumstances in- variably proved toxic in a short period of time. The toxicity of the juices