176 PHARMACEUTICAL BACTERIOLOGY 



of Caron, with a base of starch and albumen. It is used to inoculate soil 

 either by spreading it broadcast or by sowing or otherwise planting it with 

 the seed. It is not a nodule or root tubercle-forming organism, and does 

 not enter into intimate symbiotic or biologic relationship with plants. Its 

 work is simply that of binding free nitrogen, forming nitrogenous compounds 

 which enrich the soil, thus increasing the yield of any crop benefited 

 by such compounds. 



It is known that there are soil bacteria which are more especially active 

 with certain plants or groups of related plants, and this peculiarity has 

 suggested the possibility of isolating them, artifically increasing their 

 potency and using them commercially for fertilizing purposes. It is also 

 true that not all soil bacteria are beneficient. Under certain conditions, 

 pathogenic and otherwise, harmful microbes are present in great numbers 

 and become very destructive to crop plants, causing diseases of roots and 

 other plant organs. Bacillus calif orniensis, isolated from sugar beets and 

 from sugar beet soil, appears to promote the growth of sugar beets, par- 

 ticularly the seedlings. The microbic leguminous fertilizer of the Depart- 

 ment of Agriculture, Washington, D. C., is a slight modification of the 

 Hiltner method. The microbic cultures are grown in the absence of 

 nitrogen or nitrogenous compound making them nitrogen hungry, thus 

 increasing their potency to produce nodules when brought in association 

 with germinating leguminous plants. The process is patented in the 

 United States, and free samples have been liberally distributed among 

 farmers for test purposes, but the results reported have been rather 

 variable, and as a whole quite unsatisfactory. The indications are, 

 however, that future experiments will clear up the present difficulties, 

 and some of these so-called vest-pocket microbic fertilizers will no doubt 

 prove highly beneficial. 



2. THE MICROBIOLOGY OF WATER SUPPLIES 



The following is intended as an introduction to the laboratory methods 

 employed for the examination of water supplies. The usual laboratory 

 methods are chemical and bacteriological. The bacteriological methods 

 usually pertain to plate and tube cultures and have been standardized 

 and are quite generally employed in state and municipal laboratories. 

 Those interested are advised to obtain copies of the methods as prepared 

 and used by the Bureau of Animal Industry. The official methods, that 

 is the methods generally employed in the municipal and state laboratories 

 for the examination of water supplies, are incomplete as to the micro- 

 biological examination, and the organoleptic tests. Bacteria are not by 

 any means the only objectionable organisms which occur in water, as will 

 be explained. The microscopical examination of water has received some 



