1918] ANIMAL PRODUCTION. 367 



There was excellent utilization of the food. In the essential features the path- 

 ological manifestations closely resembled those observed in human pellagra. 

 The authors conclude that it seems tenable that the abnormal state may be 

 referred to a deficiency of some essential dietary constituent, presumably be- 

 longing to a group of hitherto unrecognized but essential components of an 

 adequate diet. 



ANIMAL PRODUCTION. 



A manual of Mendelism, J. Wilson (London: A. & C. Black, Ltd., 1916, pp. 

 [8'\+152, figs. 8). — A description of Mendel's law and deductions drawn there- 

 from. Various experiments in both plant and animal breeding are cited and 

 discussed in their relation to Mendel's law. Practical suggestions are made to 

 scientific breeders that should prove of value in tlieir work. 



Some applications of mathematics to breeding problems, R, B. Robbins 

 {Genetics, 2 {1917), No. 5, pp. 489-50^). — In this paper, which deals only with a 

 single pair of typical Mendelian factors, the author (1) gives some examples 

 to show the use of the methods of mathematical induction and repetition in 

 the suggestion and establishment of formulas, (2) expresses the nth term of 

 one of Jennings's series (E. S. R., 34, p. 764) as a function of n, and (3) 

 proposes a solution of the problem of inbreeding by brother and sister mating. 



Dominance of linked factors as a means of accounting' for heterosis, D. F. 

 Jones {Genetics, 2 {1917), No. 5, pp. ^66-^79, fig. i).— In this discussion of 

 heterosis the author states that, on account of linked factors, the complete 

 dominant or complete recessive can never or rarely be obtained. 



" From the fact that partial dominance of qualitative characters is a univer- 

 sal phenomenon and that abnormalities are nearly always recessive to the 

 normal conditions, it is possible to account for the increased growth in ¥i 

 because the greatest number of different factors are combined at that time. 

 It is not necessary to assume perfect dominance. It is only necessary to accept 

 the conclusion that many factors in the In condition have more than one-half 

 the effect that they have in the 2n condition. This view of dominance of linked 

 factors as a means of accounting for heterosis makes it easier to understand 

 (1) why heterozygosis should have a stimulating rather than a depressing or 

 neutral effect, and (2) why the effects of heterozygosis should operate through- 

 out the lifetime of the individual, even through many generations of asexual 

 propagation." 



The study of certain dietary conditions bearing on the problem of growth 

 in rats, C. Funk {Jour. Biol. Chem., 27 {1916), No. 1, pp. 1-lJf, figs. ^).— The 

 results reported note tlie influence of several specific substances which not 

 only might add to the nutrition but also correct deficiencies in diet. The ob- 

 servations were made during a period of nearly two years' work with several 

 hundred rats. 



Dry or germinated oats, with sodium bicarbonate or alone, proved an unsuc- 

 cessful diet for young rats. The quantity of vitamins necessary in their diet 

 is not small. One per cent of yeast added to the ration is not enough ; 8 per 

 cent at least is necessary. While yeast can be regarded as a complete food in 

 itself, replacing the total casein nitrogen by yeast nitrogen was not so satis- 

 factory as using yeast in smaller amounts for its vitamin content rather than 

 for its nutritive value. The substitution of orange juice for yeast gave no 

 results. The growth was less when milk was used instead of yeast. The use 

 of Lloyd's reagent did not give complete precipitation of the growth-promoting 

 substances, while the yeast lost some of its properties as a stimulant to growth. 



The Scandinavian methods of valuing and using feeding stuffs, J. Wilson 

 (,Dept. Agr. and Tech. Instr. Ireland (Tour., 11 (1917), "No. 2, pp. 208-217).— ThQ 



