16 INFLUENCE OF FOOD PRESERVATIVES ON HEALTH. 



been habitually consumed, keeping the body in a plethoric state^ the 

 rations were cut down somewhat, in order that this condition might be 

 removed. The quantity of the ration was, therefore, varied either by 

 increase or decrease until at the end of about ten days there was no 

 very marked daily change in weight. It was found impracticable, 

 however, to secure an absolute constancy of body weight, since the 

 climatic conditions, slight differences in the amount of exercise, and 

 variations in the quantity of excreta all combined to produce varia- 

 tions in weight (as ascertained at any given period of the day), which 

 are more or less independent of the actual quantity of food consumed. 

 In order that these daity variations may be eliminated from considera- 

 tion in the comparison of data, the average weight for the "fore 

 period " is taken as the initial point. 



The quantity of the ration having been thus determined by the obser- 

 vations of the "fore period," the "preservative period" is entered 

 upon. During this time the quantity of ration previously determined 

 is given without variation, except in case of sickness or some unavoid- 

 able condition, and to this ration a certain quantity of the preservative 

 to be studied is added. 



Borax was selected as the first preservative to be experimented with, 

 both because it is probably the most important of the commonly used 

 preservatives and also because it lends itself the most readily to pur- 

 poses of demonstration. The preservative was exhibited in two forms, 

 namely, borax and boric acid, as it was thought possible that the soda 

 entering into the former might produce some modification of the results. 



During the first part of the experiments here described the borax 

 or boric acid was mixed with the butter. In later periods of the study it 

 was deemed advisable for many reasons to administer the preservative 

 in capsules. When it was realized that a certain article of food con- 

 tained the preservative, a natural distaste for this article was devel- 

 oped, due largely, perhaps, to mental attitude. Since it was known by 

 all that preservatives were administered, there seemed to be no valid 

 reason why they should not be given in capsules in order that the 

 prejudice against any particular article of food might be avoided. It 

 is true that objection might be made to this method because it is so 

 different from the actual method of consuming preservatives when 

 added to foods in the ordinary way. Preliminary experiments with 

 the gelatin of the capsules showed that it dissolved in a very few 

 moments in the digestive ferments. a This having been established, it 

 is evident that in a few minutes after the administration of a capsule 

 containing borax its gelatinous envelope would be dissolved, and by 

 the peristaltic action of the stomach the contents of the capsule would 

 be mixed with those of the stomach. The nitrogen contained in the 

 capsule was determined (0.024 gram) and allowed for in making the 



See p. 32 for description of experiment. 



