3IO Journal of Agricultural Research voi. xvi, no. X2 



week. Regarding their physical condition after the sixth week it was 

 plainly to be seen that lot i did not have the same vigorous appearance 

 as lot 3. This was most particularly noticed with regard to the general 

 condition of the feathering which seemed slightly ruffled and imkempt 

 as compared to lot 3. This can be seen only to a degree in the illustrations 

 of these two lots (PI. 42 A, B). Their general vigor and development 

 did not appear equal to that of lot 3, and these differences became more 

 noticeable as they grew older, until, at the end of the twenty-eighth 

 week, when the experiment was discontinued, it was plainly seen that 

 lot I was in no way in the same physiological state as lot 3. 



It will also be noted from the data that after the seventeenth week lot i 

 did not gain as much as lot 3 over the same period. During these 1 1 

 weeks the gain was 234.2 gms. as against 286.5 gnis. for lot 3 ; or, in other 

 words, lot 3 made a gain 18.3 per cent greater than that made by lot i. 

 It may be of interest to point out that the cockerels of lot i showed a 

 greater variation in weight from the normal than the pullets. The 

 results of the mortality record show the same number of deaths at the 

 end of the experiment as in the control. 



In lot 2 we see that the rate of growth was retarded to such an extent 

 that at the end of the 28 weeks the average weight of a chick was 809.4 

 gms. as against 1,238.4 gm. for those receiving the ration containing 

 soybeans and 1,357.5 gms. for the control. The external sexual charac- 

 teristics were rudimentary, and the feather tracts not properly developed 

 and the fact that they retained the habits of the immature chick during 

 this entire period is of added interest. This is shown in the illustration 

 of this lot (PI. 42, C) which was taken the same day as those of lots i and 

 3, all having the same focal distance. The ration fed to lot 2 greatly in- 

 creased the mortality so that only 19 remained at the end of the experi- 

 ment, the weaklings having died earliest. Therefore we had only those 

 with the greatest initial vitality which had lived for 28 weeks on a diet 

 the biologic value of which was low. From this we would infer that the 

 individual vitality of the animal plays a very important part in" deter- 

 mining its ability to grow, and for this reason it is essential that a con- 

 siderable number of animals should be used in experiments on nutrition. 

 This would seem to follow when we realize that all of the chicks used in 

 these experiments were pure-bred and came from the same parent stock. 

 The chicks of lot 2 seemed to have a good appetite, and while they ate 

 with apparent avidity, yet they always seemed to be in search of some- 

 thing in their feed which they could not find. Regarding their ration, it 

 will be seen that it is satisfactory with respect to every necessary dietary 

 factor except the quality of protein. We are unable at this time to show 

 wherein these proteins are limited, but hope to be able to prove this by 

 experiments which are now in progress. 



