THE NUTRIENTS AND NUTh'lTION 



309 



amounts of suljstaiices associated with certain fats enables 

 the ration to supjxtrt normal growth 



In some ways the x'itam'ns might crmlely he compared 

 with the kihricants of a machine wliicli of thenisch es furnish 

 neitlier power nor material, hut which enable j)o\ver deri\ed 

 froni the consumption of the fuel to be more efficiently used.' 



The \itamins so far disco\ered and entering largely into the 

 nutrition of chicks are called "fat soluble A" and "water 

 soluble B." At least one other \itamin referred to as the 

 "antiscorbutic vitanun" is known but just what relation it 

 bears to the nutrition of birds is not understood. 



Fig. 100 





A Barrrtl Fl^iiiouth Rook mali', tJuwii on his Jt'g.s Ijocaii.^'' '>t a di'liciiricy 

 water soluble B in his ration. (I'npubhslied photograph l;ni(II.\" fuiiiisiied 

 by Hughes an<l Fox, Kansas Agricultural Fxperiinent Station.) 



As previously stated the chemical com]>ositions of these 

 substances are not known. They have not so far l.icen iso- 

 lated as separate substances and are known only liy their 

 nutritional effects. It is known that certain feciling stuffs 

 contain botli, or lack one and contain the otlier. It lias been 



' The foregoing was somewhat modified I'rorn a statement by Arnisby in 

 his "The Nutrition of F'arni Animals." 



