9 



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 to purposes of demonstra- 

 tion the most readily. 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 

 Iras deemed advisable, for many reasons, to administer the preservative 

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

 tained the preservative a natural distaste for this article was developed, 

 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 gelatine of the 

 capsules showed that it dissolved in a very few moments in the diges- 

 tive ferments. 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 that of 

 the stomach. It is hardly necessary to add that the food value of the 

 apsule in each case was determined and allowed for in making the 

 balance of the daily rations. 



In the administration of the preservative, small quantities were first 

 given, approximately as much as would be consumed in eating foods 

 preserved with borax, such as butter and meat. These quantities were 

 progressively increased for the purpose of reaching, if possible, the limit 

 of toleration of the preservative by each individual. For each variation 

 of the quantity given a separate study of the digestive processes as 

 influenced by the preservative was made. 



At the end of the preservative period, the after period began. During 

 the after period practically the same quantities of food were given as 

 in the preservative period, the preservative, however, being omitted. 

 The object of this after period was to restore the individual as nearly 

 as possible, if there had been any disturbance of his physical state, to 

 the condition precedent to the beginning of the experimental period. 



During the entire time from the beginning of the fore period to the 

 end of the after period the foods were weighed or measured and analyzed, 

 and the excreta collected and analyzed. 



