42 GENETICS [Bot. Absts. 



288. Salmon", E. S. On forms of the hop (Humulus Lupulus L.) resistant to mildew 

 (Sphaerotheca Humuli (DC) Burr.)- II. Jour. Genetics 8: 83-91. Apr., 1919.— See Bot. 

 Absts. 3, Entry 2189. 



289. Sand, K. Experimenteller Hermaphroditismus. [Experimental hermaphroditism.] 

 Pfliiger's Arch. Physiol. 173: 1-7. 1918.— See Bot. Absts. 3, Entry 1031. 



290. Sheppard, W. J. Hermaphrodite bees. Jour. Heredity 10: 160. Apr., 1919. — Se e 

 Bot. Absts. 3, Entry 1035. 



291. Southworth, W. Twinning in alfalfa. Jour. Heredity 10:182-183. Fig. 12-18. 

 Apr., 1919.— See Bot. Absts. 3, Entry 1037. 



292. Stout, A. B. Bud variation. Proc. Nation. Acad. Sci. [U. S. A.] 5: 130-134. Apr., 

 1919. — Further results fully in agreement with facts and conclusions given by author in Car- 

 negie Inst. Washington Publ. No. 218, 1915. Discusses early views on bud variation, and men- 

 tions the following tendencies in present day interpretations: (1) transmission by cytoplasm 

 rather than nucleus; (2) factor losses by segregative somatic divisions; (3) spontaneous 

 factor changes in soma. Author has studied bud variations in Colens through 14 genera- 

 tions. Sixteen new color patterns obtained; 15 were constant from first, but 6 of them also 

 appeared as fluctuating variations; one appeared only as a fluctuating variation. Selection 

 for extremes always brought progeny of marked constancy, but with further fluctuations 

 about a new mode. Concludes that recombinations of multiple modifying factors are 

 impossible'in bud propagation, and effectiveness of selection indicates actual variation in hered- 

 itary units. Reversion to parent patterns cited. Decrease of red and yellow pigment is 

 twice as frequent as increase. Most frequent bud variation was 1 : 2960. — Merle C. Coulter. 



293. Sttjrtevant, A. H., C. B. Bridges, and T. H. Morgan. The spatial relations of 

 genes. Proc. Nation. Acad. Sci. [U. S. A.] 5: 168-173. May, 1919. 



294. Terry, J. R. A wingless Wyandotte. Jour. Heredity 10: 175. Fig. 8. Apr., 1919 — 

 See Bot. Absts. 3, Entry 1038. 



295. Thompson, J. W. Breeding milk goats. Jour. Heredity 10:156-160. Fig. 3-5. 

 Apr., 1919.— See Bot. Absts. 3, Entry 1039. 



296. van der Wolk, P. C. Onderzoekingen over blyvende modificaties en hun betrekking 

 tot mutaties. [Researches on permanent modifications and their relations to mutations.] Cul- 

 tura 31: 82-105. 1 pi. 1919. — New leaves formed on branches near decayed spots on a tree 

 of Acer pseudo-platanus, suddenly become white, followed by the formation of wholly white- 

 leaved branches. These abnormal leaves and branches were remarkable not only for the color 

 of the leaves, but also for their form (with long weak tips), their leaf-stalks longer than nor- 

 mal and reddish with brown spots, their branches finely furrowed and more or less velvety, 

 their strikingly short internodes, inner bark very loose around the wood, a great well-devel- 

 oped pith, flowers greater than usual and reddish, inflorescences with few flowers, flowers at 

 each branch unisexual, — not polygamous, but male or female. The origin of this abnormality 

 resulted from the presence of a certain bacillus, cultivated by the writer in pure-cultures, 

 and called by him the "modification bacillus." A more exact description of this bacillus is 

 not given by the author; he presents only some brief communications about some of its char- 

 acteristics. This bacillus was able to penetrate the wounds of the tree, not only in branches, 

 but also in seeds; in this last case the young plants, growing from affected seeds were from the 

 beginning white-leaved and thus without vitality. From other observations writer had 

 noticed the disinfecting power of calcium oxalate; therefore he has attempted to remove the 

 infectious organism from the white branches and the affected young plants; the results were 

 very remarkable, — though the "modification bacillus" was killed by the calcium oxalate and 

 after the disinfection the infecting organism could no longer be found in the plant, its efficacy 



