26 MASS. EXPERIMENT STATION BULLETIN 355 



Streptococci in Swimming Pool Water. (Ralph L. France.) A comprehensive 

 study of the water of the college pool during times of heavy use revealed that a 

 majority of the cultures isolated were not of intestinal origin but were from the 

 mouth and nose. The numbers increased rapidly with the increase of the swim- 

 ming load, and decreased rather quickly after the swimmers had left the pool. 

 The water of the pool is treated with chlorine. Further study is planned on the 

 college pool and other available pools. A study of this kind is important because 

 of the popularity of swimming pool use in schools and colleges, and in public 

 parks and other recreation areas. 



Intestinal Bacteria Important in Nutrition 



Studies of intestinal bacteria are being made in cooperation with the Nut- 

 rition Laboratory and with Home Economics Research. It is claimed by many 

 authorities that bacteria which decompose protein food waste in the intestine 

 are detrimental to health, and that bacteria of the Bacillus acidophilus group are 

 beneficial. This theory is the basis for the treatment of intestinal disorders with 

 remedies designed to encourage the development of the acidophilus bacteria and 

 to discourage the protein-decomposing bacteria. Acidophilus milk and other 

 soured milks are prominent among such remedies. 



This laboratory has been studying the influence of mineral salts, and of mineral- 

 bearing substances such as kelp, on the ratio between the acidophilus bacteria 

 and the protein-decomposing bacteria in the intestinal tracts of white rats. Colon 

 bacilli are commonly associated with protein-decomposing bacteria and their 

 numbers are used as an indication of protein-decomposing activity. Colon 

 bacilli are responsible for liberating from decomposed proteins the supposedly 

 toxic substances which cause the condition commonly known as autointoxication. 



The public is vitamin conscious these days, and much is said and written about 

 the vitamin deficiency of our foods. Sometimes a vitamin-deficiency ailment 

 appears in a person who seems to be getting a satisfactory amount of vitamin in 

 his food. In such cases it has been claimed by some authorities that bacteria in 

 the intestine may destroy vitamins. This laboratory has studied the activities 

 of certain bacteria on vitamin C (ascorbic acid), to furnish information as to 

 bacterial destruction of vitamins. 



Detailed reports of the several studies follow. 



The Influence of Calcium Salts on the Fecal Flora of Albino Rats. (James 

 E. Fuller and W. B. Esselen, Jr.) This investigation was undertaken in order to 

 observe the effect on the fecal flora of albino rats of calcium carbonate and tri- 

 calcium phosphate when added to a 60 percent lactose diet. The basal diet itself 

 contained adequate amounts of calcium and phosphorus, and the experimental 

 diets contained enough of the respective calcium salts to furnish one percent of 

 added calcium. 



Determinations of the numbers of Lactobacillus acidophilus and Escherichia 

 coli present in the feces of the animals were made at frequent intervals for a period 

 of approximately ten weeks. There was such a marked fluctuation in the fecal 

 bacteria of the individual rats throughout the experimental period that a definite 

 interpretation of the data is difficult to make. However, the addition of one per- 

 cent of calcium in the form of tri-calcium phosphate had no marked effect on the 

 fecal bacteria of the rats. The rats receiving the calcium carbonate tended to 

 show an increase in the numbers of fecal Escherichia coli, but the numbers of 

 Lactobacillus acidophilus were not altered. 



