572 EXPERIMENT STATION EECORD. 



" The majority of the samples of white rots, eggs with yolk lightly adherent 

 to the shell, and all of the samples of sour eggs, black rots, eggs with a green 

 albumin, and eggs with yolk heavily adherent to the shell, were infested with 

 bacteria. B. coli was present in most of these samples, forming the predomi- 

 nating organism in the samples of sour eggs. The eggs with the yolk lightly 

 adherent to the shell were, chemically, slightly lower in quality than were the 

 second-grade food eggs, whereas the sour eggs, white rots, eggs with a green 

 white, and eggs with yolk heavily adherent to the shell showed much more 

 deterioration. Black rots had five times as much ammoniacal nitrogen as any 

 of these types of eggs. With the exception, possibly, of the eggs with yolka 

 lightly stuck to the shell, none of the eggs in these samples would be used by 

 the housewife or reputable baker or confectioner." 



An explanation of the technique used for the bacteriological and chemical 

 examination of eggs is included. 



Development of spurs and growth of the crest among' females of the 

 Gallinaceae, A. P£zard {Conipt. Rend. Acad. Hci. [Parish, 158 (1914), No. 7, pp. 

 513-516, figs. 3). — This reports successful operations of ovariotomy on pullets, 

 with a I'esulting development of secondary male sex characters. 



Studies on inheritance in pigeons. — I, Hereditary relations of the princi- 

 pal colors, L. J. Cole {Rhode Island Sta. Bui. 158 {WW, pp. 311-380, pis. Jf, 

 flg.l). — ^A synopsis of the principal color characteristics of pigeons is presented, 

 and the results of a study of the inheritance of certain colors of Tumbler pigeons 

 and some of their modifications are summarized as follows: 



"Only two kinds of pigment are concerned — red and black. Red {R) is 

 potentially present in all the birds, but shows only when not inhibited, and 

 when black {B) is absent, since black is epistatic to red. 



" For the full development of intensity of red and black the presence of an 

 intensity factor (/) is necessary. In the absence of this factor these colors 

 remain in the dilute condition, red appearing yellow and blaok as dun. An- 

 other factor necessary for the full expression of black is one {8) which is 

 presumed to cause the pigment to spread throughout the barbules of the feather 

 instead of remaining clumped in the central part of the old barbule cells. When 

 S is absent and the pigment is clumped as de.scribed, the appearance known as 

 blue results. The dilute condition of blue is silver. The factor S affects only 

 black pigmentation and does not produce any difference in the appearance of 

 red, at any rate that has as yet been identified. 



" White in the plumage of pigeons is due to an indefinite number of factors 

 (TTi, W2, etc.) which inhibit the production of pigment in the areas which they 

 influence. Definite patterns may result from the approach of a homozygous 

 condition for IF factors which act on particular definite regions of the plumage. 

 ' Reversion ' to the wild blue Rock Pigeon type in domesticated pigeons is due 

 simply to a recurrence of the particular combination of factors which are pres- 

 ent in Columha lii-ia. An extensive experiment on the inheritance of black and 

 red showed an overproduction of red birds in F2, the ratio being practically 2 : 1 

 instead of 3:1. This is not due to the absence of the homozygous dominant 

 class as in yellow mice. Possible explanations are offered but no definite 

 conclusion is reached. 



" Different strains or family lines appear to have different tendencies as to 

 the ratios of blacks and reds they produce in F^. Lumping all of the results 

 shows still a slight excess of reds. The ratios of intense to dilute birds from 

 heterozygotes bred to other heterozygotes or to dilutes closely approximate 

 Meudelian expectation, that is 3 : 1 and 1:1, respectively. Various matiugs of 

 the different colors give the results expected according to theory. A consider- 

 able number of illustrative matings are presented. Illustrations are given of 



