FOODS NUTRITION. 



679 



Algeria, and Tuni.«. In this discuH^^ion the anthcir gives attention to a large nnmber 

 of species of insects from which silk has l^ecn jjroduccd. The species discussed 

 belong to tlie genera Antherea, Attacus, Bonil)yx, Caligula, Saturnia, Sericaria, etc. 



FOODS- NUTRITION. 



The influence of preservatives upon the food value of milk, C. F. Doane 

 and T. M. Price {Maryland iSia. Bui. 86, jjp. 64). — Using the experimental methods 

 described in a previoiis publication (E. S. R., 1.'5, p. 674), the authors quote a number 

 of experiments with calves in which the digestibility of milk with and without added 

 preser\'atives was tested. The preservatives used were bori(! acid, borax, salicylic 

 acid, and formaldehyde, the boric acid and the salicylic acid being added to the 

 milk in tlie proj)ortion of 1:1,000, the borax in the jiroportion of 1:075, and the for- 

 maldehyde 1 : 10,000, it being recognized that ail these amounts are in excess of the 

 quantities usually regarded as sufficient. The average results of the exjjeriments, 

 whicli extend over 2 years, follow: 



Average diffestibiUti/ hij calrex of milk ivilJi and ir'iUioat prexerratlves. 



Kind of preservative. 



Salicylic acid (sid<lod justbcforo feeding) 



Boric acid (added just before feeding) 



Formaldehyde (nddeil just before feeding) 



Boric ac-id (ad(lc(l 'Jl lunirs liefor<' feeding) 



Borax (added lit hours before feeding) 



Formaldehyde (added 24 hours before feeding) 

 Salicylic aeid (added 24 hours before feeding).. 

 No preservative 



Protein. 



Per cent. 

 98. 02 

 93.84 

 95. 01 

 91.00 

 92. 22 

 94. 83 

 90.04 

 93. 52 



Per cent. 

 93.96 

 97.16 

 97.75 

 .97.57 

 97.35 

 98.36 

 92. 81 

 97.37 



From these figures it appears that on an average l.ol per cent more protein and 

 0.99 per cent more fat were digested when the milk was preserved with formaldehyde 

 than when no preservative was added. In the case of salicylic acid there was a dif- 

 ference of 3.48 per cent protein and 4.56 per cent fat in favor of the untreated milk. 

 With borax and with boric acid the difference was also in favor of the untreated 

 milk, being for the borax 1.3 i>er cent protein and 0.02 i)er cent fat, and for the boric 

 acid 2.52 per cent protein an<l 0.19 per cent fat. 



"In all of the series the comparative results were nearly the same and the results in 

 the 2 seasons' work were so nearly tlie same that it would appear that the work \\as 

 exhaustive and could be depended upon to rej^resent fairly Avell the results that 

 would be obtained if this same line of work was carried on indefiniteh'. The results 

 obtained in our work are practically the same as obtained by other workers. Borax 

 and boric acid in the experiments conducted by other men appeared to slightly pre- 

 vent digestion, while formaldehyde had the oi^posite effect. 



" From the results of this work many people may be inclined to think that milk 

 preserved with formaldehj'de is even to be preferred to milk treated with no preserv- 

 ative, as the tables evidently show it to be more digestible. . . . But it would be 

 entirely possible for the preservative to render the milk more digestible and still 

 have properties that would prove injurious. It is entirely possible for the j^reserv- 

 ative to unduly stimulate the digestive organs and in the course of time bring them 

 to a diseased condition. For this reason it is impossible to say that formaldehyde, 

 if injurious, is the least injurious of any of the preservatives used in the milk busi- 

 ness. The fact that the other preservatives used made the milk less digestible is suf- 

 ficient to condemn them. Adults could jiossibly drink such milk with impunity, 

 but in the tenement districts of cities, where the babies have a hard struggle for 

 existence, it takes a very little to turn the scale either in favor or against their 

 chances for life." 



