No. 1. July, 1920] GENETICS 119 



ized. Artificial hermaphrodites were produced, which exhibited developmenl of both sel 

 characters (penis and mammae). The psychical condition exhibited varied according to the 

 animals with which the hermaphrodite was in contact. Using a new method, i.e., placing 

 o varies inside t li<- testes, artificial ovo-testes were produced thus showing that no ism 



exists between the two sorts of sexual organs. — //. />. Good 



729. Saunders, A. P. The preservation of pollen for hybridizing. Bull. I'- m \e va 6: 

 2-9. 1918. — Review of experimental results on longevity of pollen. Tomato p »llen is ol 



kept from late summer flowers for use on green-house plants following winter. tlrape pollen 

 is viable for two months; dale palm, a ; ear or more; carnation pollen in close stoppered bottles 

 is viable for several weeks; Cheiranlhus chciri, I I days (Kdlreuter). Mentions GabtKbr'b 

 elaborate experiments on longevity of viability in pollen. Pfuxdt's met bodfl of testing pollen 

 viability arc much shorter, less work, and probably give just as accurate results as the longer, 

 more laborious method of earlier workers, such as Gartner. Pollen of many species germin- 

 ates in L5 <o _'() per cent concentration of cane sugar in water. Hanging drop culture of pollen 

 in this solution germinates in a few hours if viable. Pollen-tube formation is much slower 

 in old pollen than in fresh pollen. Pfundt found in numerous experiments, longevity of via- 

 bility of pollen was greatly influenced by humidity — wet weather decreasing, and dry weather 

 increasing the longevity of viability. Pure concentrated sulphuric acid in a desiccating 

 vessel gives very near zero humidity. 54 per cent acid + 46 per cent water gives about 30 

 per cent humidity (roughly dry-weather conditions). 37 per cent acid + 63 per cent water 

 gives 60 per cent humidity (roughly moist weather). 15 per cent acid + 85 per cent water 

 give 90 per cent humidity (muggy, rainy weather conditions). — Pfundt kept pollen samples 

 in dark at room temperature (ordinarily 65°F.) in desiccating vessels containing various per 

 cents of sulphuric acid and water mixture. Longevity of viability of pollen of various species 

 belonging to 6 very distinct orders tested by the above methods is tabulated. Pollen of 

 Prunus avium in ordinary air of room remained viable 28 days ; in 90 per cent humidity, 12 days : 

 in 00 per cent, 25 days; in 30 per cent, 102 days; in zero humidity, 126 days. Pollen of grasses 

 (Zea, Poa) thus tested remained viable only one day under any of these conditions. Genera 

 tested were Colchicum, Hemerocallis, Tulipa, Galanthus, Iris, Peonia, Trollius, Zea, Poa, 

 Prunus, Lupinus, Viola, Primula. — Wetting pollen, even for a short time, often markedly 

 decreases length of viability. Pollen of garden nasturtium (Tropaeolum) wetted two minutes 

 then artificially dried, remained viable only 2 days against 88 days for unwetted sample. Pol- 

 len tubes in most plants are not formed at low temperatures, but in such flowers as Crocus, 

 Snowdrop (Galanthus) and Christmas Rose (Helleborus), pollen forms tubes at 40°F. Cane- 

 sugar solutions should be sterilized by heating, as pollen is very susceptible to mould. When 

 perfectly fresh, only about 20 to 30 per cent of pollen is viable. Light frosts are not fatal to 

 pollen vitality. Subjected to 29-30°F. for several hours, pollen still retains much of its orig- 

 inal viability. Peony pollen long-lived, making crosses between early and late varieties pos- 

 sible and shipment practicable. Directions are given for crossing peonies. — O. E. White. 



730. Schadelin, W. Wirtschaftliche Zuchtwahl. [Practical selection.] Schweiz. Zeit- 

 schr. Forstwesen 70: 101-103. 1919. 



731. Scheurer, P. Zum Problem der Geschlechtsvorhersage. [Contribution to the prob- 

 lem of sex-prediction.] Correspl.-Blatt Schweizer Arzte 48: 1473-1483. No date. 



732. Schleip, W. [German rev. of: Kammerer, Paul. Vererbung erzwungener Form- 

 verSnderungen. I. Die Brunftschwiele des Alytes-M&nnchen aus "Wassereiern." (Inheri- 

 tance of induced changes of form. I. The callosities of the Alytes males from "water-eggs.") 

 Arch. Entwicklungsmech.' Org. 45: 323-370. PI. 10-11. 1919. (See Bot. Absts. 4, Entry 

 757.)] Zeitschr. indukt, Abstamm. Vererb. 21: 174-179. Sept., 1919. 



733. Schouten, S. L. Variabiliteit by schimmels. (Variability in Eumycetes.] Handel. 

 16e Nederl. Natuur-en Geneeskundig Congres's Gravenhage 16: 270-272. 191S. — Cases of 

 "mutation" found by the writer in his cultures of various Eumycetes, may be grouped in this- 

 way: 



