DAIRY FARMING— DAIRYING AGROTECHNY. 179 



an alkaline reaction. The micrococci varieties which grow in groups of 4 pre- 

 dominated to the extent of 95 per cent. One variety of micrococci seemed to 

 be dominant and was present in frequency of occurrence 22 times in comparison 

 to other varieties which were present 9, 8, 7, 3, 3, and 2 times, respectively. 



" The most abundant source of bacteria that get into milk is the surface of 

 the cow. Some fall on the cow with the dust that settles into the hair. Others 

 accumulate from contamination with cow feces. Organisms from this source 

 are the most serious and most objectionable."' A gram of the powder obtained 

 by currying the cow was found to contain 207,000,000 organisms. As to hay as 

 a source of bacteria 28 tests, continuing weekly from October 17 to May 28, 

 were made of the number of bacteria per gram of a haj^ including timothy, red 

 top, rowen, semiswail, and swamp hay, taken from all parts of the hay loft. 

 The average number of bacteria per gram for all these tests was 16,800,000. 

 '■ In order to compare the numbers of organisms on hay and on grass from early 

 spring to time of cutting, tests were made of the numbers on grass in the dif- 

 ferent stiiges of development. The sources of grass were pasture land, semi- 

 fertile fields, very fertile fields, and near buildings. Clover and rye were inci- 

 dentally included. The average number of bacteria per gram for all samples 

 was 1.5,000,000, a number nearly the same as that found in cured hay." 



To ascertain the kinds of bacteria that get into milk from hay " twenty-five 

 of the most abundant kinds were picked out and analyzed. Ten of these, or 40 

 per cent, were spore-forming bacteria; 18, or 72 per cent, Avere liquefiers (decay 

 and decomposition bacteria) ; 22, or 88 per cent, were rod-shaped bacteria, and 

 12 per cent were cocci or spherical bacteria ; IS, or 72 per cent, were motile 

 capable of swimming around in milk and getting into all parts of it, causing 

 nuK'h more rapid changes than those that are motionless." 



According to the authors, the bacteria found on grass are mostly from soil 

 contamination. To determine whether these grow on the surface of plants 

 " the first spring growth of grass on April 18 was clipped off with sterile shears 

 and a gram was plated for numbers. There were found 455,000 per gram. 

 Over this spot was placed a bell jar, to keep out all contaminations. On the 

 thirtieth of April a gram of grass was taken from under the bell jar and plated 

 for numbers. The number of bacteria now was only 114 per gram, showing 

 that the bacteria on grass are largely bacteria from some other source. If they 

 do multiply on grass it is at a very slow rate. There was no evidence of 

 Bacteiium lactic acidi present on this sample of grass." 



Grain feeds were found to be liberally stocked with organisms. The ex- 

 aminations made show that the percentage of acid organisms is more than twice 

 as large, while that of liquefying organisms is only half as large, as that for 

 hay. 



The agency of flies as a source of bacteria was indicated by tests showing 

 that from 414 flies an average of about 1,250,000 bacteria for each fly was 

 obtained. The relation of the prevalence of flies to an increase in intestinal 

 diseases is discussed. 



The number of bacteria that could be washed from the hands of a milker who 

 had * been working around the farm previous to milking was found to be 

 45,000,000 before the hands were washed. 



Bacterial growth and chemical chang'es in milk kept at low temperatures, 

 Mary E. Pennington (Jour. Biol. Chem., J, (1908), Ao. 4-5, pp. 3o3-39S; abs. in 

 Hcicnce, n. scr., 27 (1908), No. 687, p. 331).— lu milk kept at a temperature of 

 — 0.55° C. there was a steady inci'ease in the number of organisms for 5 or 6 

 weeks. Acid formers were in lower proportion and liquefying organisms in 

 higher proportion than is commonly found. Certain species were especially 

 resistant to cold and frequently were predominating or almost in pure culture at 



