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sightly and irremovable blotches on the fabric. The preparation of gelatin, 

 maccaroni, lime juice and wines requires precautions to be taken to prevent access 

 of air containing spores of fungus. It would not be difficult to extend the list of 

 noxious fungiises, but enough has been said to show that man's person, food, 

 clothing, building materials, and occupations are all injured by divers species of 

 fungus. In proportion to tlie amount of injury tliey cause, they become important. 

 It must be desirable, therefore, that their structure, habits, and life history should 

 be carefully studied, so that advantage may be taken of every opportunity of 

 lessening or preventing their injurious effect. 



The chemical process of nutrition in funguses is not the same as in other 

 vegetables. Funguses do not convert inorganic matter into organic compounds. 

 They possess a vital force capable of overcoming the natural play of chemical 

 affinities, and they live by appropriating the constituents of the compounds tliey 

 are thus enabled to decompose. Fermentation is notliing more than the manifest- 

 ation of this process of decomposition. Such fermentations as are not produced 

 by the immediate action of living cells, are called indirect. They are caused by 

 the intervention of nitrogenous soluble matters elaborated by living cells. These 

 soluble ferments are often stored up till circumstances require their alterative 

 action. It would seem that most organic substances are subject to fermentative 

 changes, often occasioned by a special ferment plant. There are other ferment 

 plants besides those that are recognised as funguses. Sugar undergoes several 

 direct fermentations — the alcoholic, lactic, viscous, and butyric. Alcohol by 

 fermentation becomes acetic acid ; albuminous matters and urea are transformed 

 into ammonia by processes of fermentation. 



It will be interesting to sanitarians to know that there is reason for 

 believing that the conversion of ammonia into nitric acid is caused by the presence 

 of a fungus ; tliis process has be^n called nitrification. It goes on constantly in 

 soil that is saturated with decomposing animal matter. The saltpetre of commerce 

 is for the most part imported from India, and is obtained by washing it out of the 

 soil. Nitrification has long been known, and carried on artificially. Pasteur 

 suggested that it might be a fermentative change, and some recent experiments 

 show that he was probably correct. MM. Muntz and Schliessing passed sewage 

 water through a porous medium, for eight days there was no change in the amount 

 of ammonia, but after that time ammonia disappeared and nitric acid took its 

 place. This experiment is only explicable by supposing that germs of a ferment 

 plant were present and took time to mature. This notion was confirmed by 

 another experiment, which proved that the presence of antiseptic vajjours sus- 

 pended the action. Among fermentations, the alcoholic takes the first rank, it is 

 the most familiar and the most easily studied. There has been considerable 

 difierence of opinion as to the nature of the plant which causes this fei-mentation. 

 Most English authorities have considered till lately that it was a modified growth 

 of a common mould called Penicillium. German mycologists make it into a genus 

 belonging to the class Torulae, among funguses. They call the genus Saccharo- 

 myces, and include within it several species. 



