7.8 



determination was made both in the extracted /at and the residue. In 

 this case the quantity of lecithins is quite high. The mean for all the 

 tendons, as determined, was 0.19, with a maximum of 0.45 and a mini- 

 mum of 0.08. 



In Table 18 the total percentages of lecithin in the whole animal, with 

 the exceptions noted in several of the tables, are found. The mean 

 percentage is 0.23, the maximum 0.42, and the minimum 0.11. 



In submitting the above discussion it is but just to state that at the 

 commencement of the analytical examination it was not our purpose to 

 determine the lecithin "at all. Had it been so, the determinations would 

 have been made in a somewhat more satisfactory manner. The data, 

 however, as submitted are, nevertheless, valuable, and with the restric- 

 tions noted in the different tables may be relied upon as a basis for 

 economic studies. 



CONCLUDING OBSERVATIONS. 



In conclusion it may be stated that although work of the kind which 

 has just been discussed is extremely onerous and time-consuming, yet 

 it appears from a study of the results obtained to be a further contri- 

 bution to our knowledge of dietetic science. All systems of true die- 

 tetic studies must rest first of all upon well-established chemical data. 

 No valuable conclusions in regard to the dietetic value of any food can 

 be obtained without first having ascertained its exact chemical compo- 

 sition. This having been done, the further study of its dietetic value 

 rests also upon its chemical properties, as, for instance, the coefficients 

 of digestibility. It appears advisable, therefore, considering the char- 

 acter of the data which have been presented, to recommend that studies 

 of this kind be continued with all the classes of animals used as foods 

 in this country. It would be advisable, if possible, that in studies of 

 this kind, the animals be slaughtered at or near the point where the 

 chemical examination is to be made; or, if this be not convenient, that 

 a representative of the Chemical Division be present at the time of the 

 slaughtering for the purpose of ascertaining the quantities of blood, 

 hair, and excreta from the different animals and obtaining representa- 

 tive samples thereof for chemical examination. 



Our systems of feeding and our environment develop types of animals 

 which are quite distinct from those grown in other lauds, and therefore 

 the data which are obtained on animals in other countries are not 

 strictly applicable to studies of the economic science of food production 

 and food composition in this country. 



