372 EXPERIMENT STATION RECORD. [Vol. 36 



practically the same as that of the offspring of dams in the classes five to seven 

 and eight to ten years old. 



The relation of the age of both parents to the size of the cannon bone of their 

 offspring was studied. The average size of cannon bone was slightly greater in 

 the female offspring of parents both of which were under ten years old than 

 of those from parents either one or both of which were over ten years old. In 

 studying how the measurements of the cannon bones of the female offspring 

 deviate from those of their dams it was found that there was a significant 

 variation only when both parents were ten years old and younger, and in this 

 case the daughters were larger than the dams in cannon bone size. 



The author suggests the following conclusions as a result of these studies: 

 '■ The age of the parent has an influence on the circumference of the cannon 

 bone of the offspring. Immature parents two to four years old give offspring 

 with the same measurement of tbe cannon bone as parents as old as five to 

 seven years. Parents older than ten years considered as a class give offspring 

 with lighter cannon bones than parents ten years old and younger. In the 

 breed examined there was found a larger percentage of individuals over average 

 size whose parents were ten years old or younger. On the other hand, the 

 average individuals and those smaller have parents which are just as fre- 

 quently under ten years old as they are over. In other words, the lighter 

 classes of cannon bone come as frequently from young as from old parents, but 

 the heavier classes seem to come more frequently from younger parents. There 

 seems to be some basis for the current opinion among breeders of Gudbrandsdal 

 and other heavy breeds that young parents give better offspring than older 

 parents." 



The connection of these data with current genetic hypotheses and conceptions 

 is discussed. 



Mules that breed, O. Lloyd-Jones {Jour. Heredity, 7 (1916), No. 11, pp. 

 494-502, figs. 7). — The author comments briefly upon a number of recorded 

 cases of fertility among mules and reviews physiological studies of the germ 

 cells of these animals, which indicate that the chance of mule breeding is very 

 slight. 



The effect of the amino-acid content of the diet on the growth of chickens, 

 T. B. Osborne, L. B. Mendel et al. (Jour. Biol. Chem., 26 (1916), No. 2, pp. 

 293-300, pi. 1). — Feeding experiments are reported in which two pairs of 

 chickens (Rhode Island Reds) were fed, the one on a ration consisting of corn 

 gluten, " protein-free " milk, starch, butter fat, and lard, and the other on the 

 same ration plus lactalbumin. The mixed protein of the corn-gluten ration 

 was considered to yield about 1 per cent of lysin, while the ration with the 

 lactalbumin yielded a considerably larger quantity. During the course of the 

 experiment one chick of each pair died from causes not ascertained. 



The chick receiving the corn-gluten feed made a total gain in 55 days of 

 52 gm., while the chick receiving the corn gluten plus lactalbumin ration made 

 a gain of 283 gm. in the same period, 



It is indicated that the " observations corroborate, for the chick, the ex- 

 perience which we have previously published regarding the unlike value of 

 different proteins in the nutrition of growth." 



Further experiments are reported which demonstrate that cottonseed flour 

 forms a suitable adjuvant for the proteins of corn gluten, as two chicks fed 

 on such a ration made gains of 284 and 322 gm., respectively, in 53 days, as 

 compared to a gain of only 52 gm. in 55 days by the chick fed the corn- 

 gluten ration noted above. 



It is indicated that in view of the work recently reported by Drummond 

 (E. S. R., 35, p. 472), in which it was maintained that it is impossible to rear 



