Ap'ml. 1820] GENETICS 143 



980. Blakeslee, ALBERT F., and B. T. AVERT, Jr. Mutations in the Jimson weed. 

 Jour. Eeiedity 10: 111-120. Fig. 5-15. Mar., 1919. — An article in which the authors name and 

 describe several mutative variants of sudden, though rare occurrence which transmit their 

 characters— chiefly through the female sex — to only a part of their offspring. One, particu- 

 larly, designated N. S., proved nearly sterile with normal plants though it is self-fertile and 

 breeds true. — .1/. J. Dorsey. 



9S1. Bridges, Calvin B. Vermilion-deficiency. Jour. Gen. Physiol. 1: 645-656. July 

 20, 1919. — A lethal sex ratio in Drosophila mclanogasler was found to be due not to a simple 

 mutation but to a deficiency (regional mutation or loss or "inactivation") of a portion of sex 

 chromosome. Deficient region includes vermilion locus and flies carrying both vermilion 

 and vermilion-deficiency look vermilion. It extends to the right of vermilion for a distance 

 not exceeding three units. It includes also one or more loci to the left of vermilion because 

 its lethal effect is not balanced by "vermilion sable duplication" which is an extra piece of 

 chromosome carrying vermilion and several factors to its right. It is probable that there is 

 no crossing over at all within the deficient region, that crossing over in adjacent regions is 

 cut down markedly and in more distant regions is either unaffected or slightly increased. All 

 these effects indicate a disturbed synaptic relation. Cytological preparations of deficiency 

 proved unsatisfactory. The stock was lost because of injurious action of deficiency on via- 

 bility, fertility, and productivity. — Alexander Weinstein. 



982. Calkins, Gary N. Restoration of vitality through conjugation. Proc. Nation. 

 Acad. Sci. [U. S. Amer.] 5: 95-102. Tables IS. 1919.— Neither the theory that conjugation 

 restores vital activity to an optimum nor that it results in variations has been conclusively 

 established. Calkins finds "that conjugation, in the ciliated protozoon Uroleptus mobilis, 

 actually restores vitality to full metabolic vigor." Endomixis or asexual reorganization 

 with restoration of vitality, occurs in Uroleptus mobilis while encysted, and was not allowed 

 to take place in the five lines used in this work. These five lines were derived from the de- 

 scendants of a single exconjugant at its third division. After 313 generations, during which 

 vitality progressively decreased, the series died out. Specimens, not among those isolated 

 daily, were allowed to conjugate and four filial series of these exconjugants were begun at 

 the 78th, 147th, 237th, and 311th generations. The first of these died in the 348th generation; 

 the second died in the 271st generation; and the third and fourth series were still dividing 

 actively in the 277th and 236th. Four other series were started from these filial series. It 

 was found that conjugation did not begin to take place until from 50 to 70 days from the start 

 of the series. This is the period of sexual immaturity. Division rate indicates the degree 

 of vitality and since the maximum division rate is restored by conjugation in specimens taken 

 from the series at various stages in the decline of vitality the conclusion is reached "that con- 

 jugation results in the complete restoration of vitality regardless of the age or the weakened 

 condition of the parent protoplasm, . . ." — R. W. Hegner. 



983. Collins, G. N. A fossil ear of maize. Jour. Heredity 10: 170-172. Fig. 7. April, 

 1919. — Comment on a description by F. H. Knowlton of fossil ear of maize from Peru. While 

 the fossil form is not identical with any of the existing types, it presents no new characters and 

 therefore appears to be simply a different combination of characters. — M. J. Dorsey. 



984. Conklin, Edwin G. Heredity and democracy. A reply to Mr. Alleyne Ireland. 

 Jour. Heredity 10: 161-164. 1919.— A reply to Ireland (Jour. Heredity 9: 339-342. 1918. 

 [See also Bot. Absts. 3, Entry 261]) in which it is urged that there is no reason for the conclu- 

 sion that heredity and democracy are incompatible. [See Bot. Absts. 3, Entries 1000, 1002.] 

 — M. J. Dorsey. 



9S5. Coulter, J. M. Evolution of maize. [Rev. of: Weatherwax, Paul. The evolu- 

 tion of maize. Bull. Torrey Bot. Club 45: 309-342. Fig. 36. 1918.] Bot. Gaz. 67: 104. 

 Jan., 1919.— See Bot. Absts. 1, Entry 503. 



