Pathological mycology : an enquiry into the etiology of infective diseases / by G. Sims Woodhead and Arthur W. Hare.

  • Woodhead, German Sims, Sir, 1855-1921.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: Pathological mycology : an enquiry into the etiology of infective diseases / by G. Sims Woodhead and Arthur W. Hare. Source: Wellcome Collection.

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

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    commencement of the process and its final issue, there was consider- able risk of extraneous contamination. It is nevertheless unjustifiable to urge the extreme difficulty of the quest as the probable cause of a fallacious result; and the position which one must therefore almost of necessity occupy at present is one of expectancy, until more conclusive investigations have been completed, and the whole question put in such a position that its settlement may become a possibility. The evidence on this point so far produced tends strongly against the transmutation theory; but as yet no sufficient mass has been brought forward on either side to render a final decision possible. Requirements of Micro-Organisms. 18. At this stage it will be well, shortly and in general terms, to state what are the main vital necessities of a micro-organism which deter- mine the relation it will take up to the various tissues or media in which it may occur. Lying as it does on the borderland between the animal and the vegetable worlds, its nature is of a but slightly differ- entiated type, and its requirements are proportionately simple. An analysis of its chemical constitution shows it to be composed of 88 per cent, of water, 2 per cent, of inorganic ash, and 10 per cent, of organic compounds. This composition gives a general indication as to what substances it will chiefly require to sustain its life and development; and it is found accordingly that its food must consist very largely of watery elements. The organic compounds requisite to its Ufe are chiefly those rich in carbon and nitrogen; and the minerals which it specially needs are potassium and compounds of phosphorus. Micro-organisms differ to a very great extent as to their dependence upon, or independence of, the presence of free oxygen. So marked is the former condition in certain genera—as, for instance, the moulds— that they do not grow actively except on free surfaces, where they can obtain oxygen directly fiom the atmosphere, or under such con- ditions as permit of their readily obtaming it. Other genera, and notably those of the yeast series, are capable of passing through all the sta'^es of their life-history without obtaining oxygen, except the