36 MASS. EXPERIMENT STATION BULLETIN 374 



2. A series starting with a high-carbohydrate diet (Purina fox chow and 

 lactose) to induce a high initial acidophilus fecal flora. After preliminary 

 feeding periods on these diets, raw and pasteurized milk with and without 

 iodine were added as will be indicated later. Samples of feces were ex- 

 amined twice each week throughout the experiments. Examinations were 

 made for gas production and hydrogen sulfide production, respectively 

 indicative of fermentation and putrefaction; total aerobic bacteria counts; 

 coliform bacteria counts; acidophilus bacteria counts. 



High-protein Diet 



Twelve young rats were fed hamburg steak for four weeks, with agar- 

 agar added for bulk. Then the animals were separated into four groups 

 and milk was added to the diet as follows: Group 1, pasteurized milk; 

 Group 2, pasteurized milk with iodine added at the rate of 2 milliliters per 

 quart of milk; Group 3, raw milk; Group 4, raw milk with iodine added 

 at the same rate as with group 2. After eight weeks on these diets, the 

 hamburg steak was discontinued and the animals were given only the 

 several milk diets, the amount of milk being increased to compensate for 

 the amount of meat withdrawn. This feeding was continued for four 

 weeks more. 



High-carbohydrate Diet 



Twelve young rats, practically identical in age and size with those in 

 experiment 1, were fed for four weeks on Purina fox chow and lactose. 

 Then the rats were separated into four groups as above and given similar 

 milk supplements. After eight weeks on the milk supplements, the fox 

 chow was discontinued and the several kinds of milk were given as the 

 only food for another four weeks. 



Comment 



The amount of food given the rats was sufficient to provide adequate 

 nourishment; and the total amount of iodine administered per day to 

 each rat of groups 2 and 4 of each experiment was somewhat greater, 

 when calculated on a basis of body weight, than would ordinarily be con- 

 sidered adequate for human consumers. i Pasteurized milk, as well as raw 

 milk, was included in the experiment because some objectors to pas- 

 teurization contend that heating the milk kills acid-producing bacteria, 

 and that the drinking of the milk consequently encourages putrefaction 

 in the intestine and gives putrid stools. 



When the data from these experiments were assembled, it became evident 

 immediately that the iodine had not exercised either a demonstrable stimu- 

 lating or inhibiting action on any of the fecal bacteria. Gas production and 

 hydrogen sulfide production responded in the usual way to the effects of the 

 hamburg steak, the Purina fox chow, and the milk, and without any ref- 

 erence to the presence or absence of iodine. The same was true of the 

 total-bacteria counts, the B. coli counts, and the acidophilus counts. Experi- 

 ments on the effects of meat, milk, and cereal diets on the fecal flora of 

 animals and man are so well known that tabulation of results is not justi- 

 fied here. 



The different bacteria counts from individual rats, or from rats of any 



'The exact data wall be furnished to anyone interested, on receipt of request, by the 

 authors of this section of the report. 



