SUPPLEMENT 



Bacteria that cause diseases enter the system by different avenues, 

 through abrasions of the skin perhaps, or by way of the lungs or the 

 alimentary canal. Because our state is to such an extent a sanitar- 

 ium for consumptives, it is well to emphasize the fact that the chief 

 danger of infection is from bacilli liberated in expectoration, a dan- 

 ger that can be met by proper care and cleanliness. Typhoid fever 

 arises usually only when the germs enter the alimentary canal, and 

 is therefore a preventable disease. 



The bacteria that cause putrefaction split up albuminoid compounds 

 into various gases and liquids. In the earlier stages some of the pro- 

 ducts have very offensive odors ; later on nitric acid, so essential to 

 plant life, is evolved. The unused parts of carbo-hydrates also are 

 returned in various forms to the surrounding air or water. There are 

 other very useful bacteria whose presence in the roots of leguminous 

 plants is denoted by warts or tubercules. They are apparent even in 

 small seedlings, in bur-clover or lupine for instance. It seems to be 

 well established that in this case the bacteria can fix and store up 

 free nitrogen for the use of the higher plants ; that is, this is not a 

 case of parasite and host, but is true symbiosis. The souring of milk 

 and the ripening of cream are also due to bacteria. There are, in 

 common daily experience, many other evidences of the presence of 

 bacteria. The cloudiness of water in which cut plants have been 

 standing is a visible evidence, so are the bright red spots often seen 

 on fermenting starchy foods. 



Yeast plants are nearly as minute as bacteria, and their study 

 requires high powers of the microscope. They split up grape sugar 

 into alcohol and carbon dioxide, thus causing alcoholic fermentation. 

 They can reproduce very rapidly by a process called budding, sending 

 off little sprouts or buds that break off and become independent 

 plants. The facts that yeast plants have another method of repro- 

 duction, and that their affinities are doubtful, need not be discussed 

 here. 



Mould can be grown with very little trouble. Bread moistened and 

 closely covered will grow a good crop in four or five days. Usually 

 the growth is so vigorous, that not only the substratum of food, but 

 the sides of the dish and the cover as well, become covered with tiny 

 clusters of spore-bearing stalks, connected by runners. These clusters 

 are clearly perceptible without even a lens, for the stalks are several 

 millimeters long. They are easily handled, and a low power of the 

 microscope should be used. It is best to mount in glycerine, adding 

 a drop of alcohol to expel air. The filaments of the mould are not 

 divided into cells. From the first they branch or interlace, forming 



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