ANNUAL REPORT, 1936 23 



DEPARTMENT OF BACTERIOLOGY 

 Leon A. Bradley in Charge 



Microbiological Examination of Dried Foods. (J. A. Clague and James 

 E. Fuller.) This work has been published by the senior author (Food Research, 

 1: 45-59, 1936). No further work is contemplated at this time. 



Detection and Significance of Escherichia Coli in Commerical 

 Fish and Fillets. (F. P. Griffiths and James E. Fuller.) This was a joint 

 study with the U. S. Bureau of Fisheries. The results were published (Amer. 

 Jour. Pub. Health, 26: 259-264,1936). The study is not being continued. 



The Influence of Bile and Bile Salts on Aerobacter Aerogenes. 



(James E. Fuller.) A preliminary statement has been published (Mass. Exp. 

 Sta. Bui. 327, p. 21, 1936) concerning the influence of one percent concentra- 

 tions of ox bile, sodium glycocholate, and sodium taurocholate on the bio- 

 chemical reactions of Aerobacter aerogenes. It was thought that some variations 

 in these reactions might be induced by cultivation of various strains of the 

 organism in the presence of bile and bile salts. No variations were observed 

 after five months' cultivation of the organisms, with weekly transfers to fresh 

 media. Higher concentrations of the bile and bile salts are now being employed. 

 To date, after two months of weekly transfers, the cultures continue to exhibit 

 the same biochemical reactions as at the beginning of the experiment. Indi- 

 cations are that under the conditions of the experiment bile and bile salts do 

 not induce variations in Aerobacter aerogenes cultures. 



Lipolytic Activity of Gram-Negative Intestinal Bacteria. (James E. 

 Fuller and E. W. Harvey.) This study was planned to investigate the extent 

 of lipolytic activity among Gram-negative bacteria common to the human in- 

 testinal tract in health and in disease, and to determine whether or not there 

 was any correlation between the lipolytic activity of the bacteria employed 

 and their ability to digest proteins and carbohydrates. Lipolytic activity was 

 not general among the Escherichia or Aerobacter cultures employed, but 13 

 of 25 intermediates of the group studied possessed active lipolytic power. No 

 lipolysis was observed among the strains of Salmonella, Eberthella, or Shigella 

 studied. There did not appear to be any relation between lipolytic ability and 

 either proteolysis or carbohydrate utilization. 



Influence of Added Iodine on the Bacterial Flora of Milk. (James E. 

 Fuller and George S. Congdon.) Iodine was employed in the form of tincture, 

 Lugol's solution, and colloidal iodine. The quantity of each was varied to 

 determine the amount of iodine required to inhibit bacterial growth in milk. 

 More iodine was required to inhibit bacterial growth in milk of high initial 

 bacteria counts than in milk with low initial counts. Tincture was found to 

 be more effective than Lugol's solution. Less work has been done with the col- 

 loidal iodine, but indications are that it will approximate the tincture in in- 

 hibiting power. 



Effect of Raw, Pasteurized, and Iodized Milk on the Fecal Flora of 

 White Rats. (Wm. B. Esselen and James E. Fuller.) This study was under- 

 taken to investigate a claim that pasteurized milk has a tendency to induce 

 intestinal putrefaction while raw milk does not, and that the addition of iodine 

 is more effective than pasteurization as a means of controlling the bacterial 

 growth in milk. Four series of white rats were maintained on the following 



