ANIMAL PRODUCTION, 273 



which it offers in explanation of the ialieritaiice of immunity, etc.; (4) and 

 tlie i)ossible light which this extremely simple form of inheritance may throw 

 upon the mass of developmental and inlieritance phenomena which seem to be 

 of a much higher order of complexitj^" 



A l)il)lioj;raphy of the subject is appended. 



Coloration of the milk in lactating animals and staining' of the growing 

 adipose tissue in the suckling' young, S. li. and Susan 1*. Gage {Aiiat. lice, 

 ,)' (J'JO'J), Ao. -'/, 1)1). 20 J, 20 i).— A continuation of earlier work (E. S. K., 20, 

 p. 1170). 



The adipose tissue of half-grown white rats showed a pink coloration within 

 5 days from the time the stain Sudan III was given in the feed. Contrary to 

 expectations, newly born young of rats and guinea pigs did not show traces of 

 the stain that had l)een mixed with the mother's food during gestation, which 

 is proof that it did not pass through the placenta. At the end of 8 days after 

 birth young rats showed an abundance of pink adipose tissue and the milk 

 tilling the stomach was so pink tliat it showed through the stomach wall. 



[Studies on the development and the pigmentation of feathers], O. Riddle 

 {Biol. Bui. Mar. Biol Lah. Woods Hole, 12 (1007), No. 3, pp. 165-171,, figs. 3; 

 Ut (1908), Nos. 3, pp. 163-176, figs. 2; 6, pp. 328-370, pis. J,, figs. 5).— These 

 studies relate chiefly to the development of the feather, the structural differ- 

 ences between pigmented and nonpigmented areas of feathers, and the causes 

 of pigment distribution. 



The different types or defects in the structure of the adult expanded feather 

 are thought to be due to a reduced nutrition caused by a daily lowering of the 

 blood pressure. The rate of growth varies greatly in different feather tracts 

 of the bird. " In a Plymouth Kock it was, in the primaries, secondary coverts 

 and body coverts, 4, 2.25, 1.75 nnu. daily resi)ectively. In general, the rate 

 bears a rather definite relation to the ultimate length of the feather; and is 

 less at the proximal than at the distal end of the feather. . . . 



"The ring dove shows a still more rapid feather growth. Seven mm. of 

 growth in 24 hours has occasionally been recordetl in the rectrices of these 

 birds. The average for these birds is, rectrices 5 to G mm., primaries 5 to G mm., 

 upper tail coverts 4 mm., primary coverts 4 mm. It will be recalled that this 

 is also the order of frequency for the ai)pearance of the defective areas in the 

 various feather-tracts. This and kindred observations establish beyond doubt 

 that the frequency of appearance of obvious fault-bars in feathers is directly 

 related — one might say proportional to the rate of growth." 



"Under starving conditions the rate of linear feather growth is not affected 

 until the third or fourth day; after this the rate falls rapidly (doves). Fault- 

 bars can be readily produced experimentally by reduced feeding; by the feed- 

 ing of the fat stain Sudan III, which seems to 'tie up' certain foods; by very 

 strong mechanical crumpling sufficient to break the tissues and blood vessels; 

 and by lowering the blood pressure with amyl nitrite. . . . Previous results 

 showing that the lowest (daily) temperatin-e of birds occurs in the early hours 

 of the morning (1 to 5 a. m.) have been contirmed. . . . The fundamental 

 bars furnish the starting point for all evolutionary studies on the color-charac- 

 ters of birds." 



Further contributions to the theory of heredidty, W. WiiiNBEiui (Arch. 

 R<iss('ii H. (icscll. Biol., 7 (1910), No. 1, pp. 35-'i;i). — A discussion of the Galton- 

 Pearson ancestral law (E. S. K.. 21. p. 771). 



The author contends that biometrics has been ovt'rvalued by its advocates. 

 It is, nevertheless, a valuable means of supplementing, though it can not sup- 

 plant, breeding experiments and individual analysis in the study of heredity. 

 It is further stated that the real point at issue between the biomerticiaus and 



