614 Varietäten, Descendenz, Hybriden. 



sicum annuum. (Sei. Proc. Roy. Dublin Soc. XIV. W 25. p. 328— 

 335. 1915.) 



The results obtained are summarized as under. In Capsicuni 

 fruits, red is dominant to yellow, and appears to be a simple domi- 

 nant to chocolate and orange. The differences in colour of unripe 

 green fruits are due to the Variation in the number of chromato- 

 phores. The colours of ripe fruit are due to red, chocolate, orange 

 and yellow plastids. 



The red and chocolate pigments when ripe are only liquids 

 which have not been obtained in a crystalline condition. They are 

 distinguished from lycopin, Carotin, xanthophyll by this, and by 

 their ready solubility in cold alcohol and in petroleum ether. Such 

 Solutions become colourless when allowed to evaporate in sunlight. 

 Carotin is moderately soluble in piridine and yields crystals from 

 this solvent similar to those from etherial Solution. 



The amount of peroxidase present in all Capsiaim fruits appears 

 to diminish as thej'- ripen, and bears no simple relation to the va- 

 riety of fruit. The enzyme is frequenth'- present only in the epider- 

 mis, while the deeper tissues may contain an inhibitor with a 

 strong reducing action. F. Cavers. 



Campbell, D. H., The nature of Graft Hybrids. (American 

 Naturalist. XLV. p. 41—53. 1 Fig. IQll.) 



A discussion of Winkler's studies on Graft Hybrids, to which 

 the author added some general considerations. Jongmans. 



Castle, W. E., On sex-chromosomes in hermaphroditism. 

 (American Naturalist. XLV. p. 425 — 430. 1911.) 



This paper chiefly contains a discussion of the results obtained 

 by Boveri and his students in certain nematodes, as to the deter- 

 mination of sex. Jongmans. 



Collins, G. N., A more accurate method of comparing 

 first-generation maize hj^brids with their parents. 

 (Journ. Agric. Research. III. p. 85—91. 1914.) 



So large a proportion of tirst generation maize hybrids have 

 been found to give increased yields and the increase is frequently 

 of such magnitude that the utilization of this factor of productiveness 

 becomes a practical question. It is therefore highly desirable to 

 understand the reasons why some crosses give favorable results 

 and others give little or no increase over the yield ot the parents. 

 A necessary step in this direction is to develop a reliable method 

 of measuring the effect of crossing, apart from other factors that 

 influence yield. 



The development of satisfactory methods of comparing the 

 yield of first-generation hybrids with that of their parents has been 

 retarded by 1) a failure to fulh^ appreciate the importance of indi- 

 vidual diversity in hybrids, 2) the abnormal behavior of self-polli- 

 nated maize plants, and 3) the difificulty of securing for comparison 

 hybrids and parents with identical ancestry. It is believed that the 

 method here described avoids these difficulties and affords more 

 accurate means of comparing first-generation maize hybrids with 

 their parents. 



