59 



Knowledge of this fact serves to give uniformity to the first generation 

 and avoids the difficulty of continuing through subf-equent generations 

 breeding in which the results secured will not be uniform. The 

 necessity cf using large numbers of individuals was pointed out. In this 

 there w;.s great advance over Mendel's predecei^sors. After having 

 secured hybrids they should be carried through many generations. 

 Mendel in all cases carried his experimets to the third aud fourth 

 and in some cases to the fifth and sixth generations. Summing up 

 the methods of Mendel, the author states that hybridists who desire 

 to follow the footsteps of Mendel and help elucidate the problems of 

 inheritance will find it essential in their work to select parents pnssess- 

 ing characters which are at once single and constant differential and 

 dominant, and they must also take care to raise large numbers of 

 individuals through many generations. , 



A paper by Hugo de Viies, director ot the Botanical Gajdens Amster- 

 dam, Holland, discussed Artificial Atavism. Atavism was defined as 

 the occasional restoration of an old type in a compound cross. Crossing 

 is said to not only combine characters, but to separate them. Among 

 flowers as ordinarily listed in catalogues, there is usually the ordinary 

 wild color as well as a white term, with various intermediates. If a 

 cross be made between the white form and some of the intermediates, 

 the resultant hybrids will fall into types, some of which return to the 

 original color. The color variations and reversions produced by various 

 crossings were shown by illustrations of well-known varietie^^. It is 

 said to be possible to split up and produce new colors by crossing the 

 original or wild color with any of the white forms. The results obtained 

 usually follow the principles laid down in Mendel's law. A number of 

 instances were cited in which it is shown possible to produce atavism 

 artificially. 



In commenting upon this paper, Professor Bateson stated that he 

 believed synthesis in plant breeding, although sometimes apparent is not 

 truly possible. A compound character consisting of 3 or more compo- 

 nents, he believes, can not be recomposed from its original forms. 



Some suggestions for Plant Breeding were made in a paper by Max 

 Leichtlin, of Baden-Baden, Austria, which was read. In crossing plants 

 the author states that the selection of a suitable time for crossing is of first 

 importance. A warm, cloudy day offers the best conditions for about 60 

 per cent, of plants. For some a dry atmosphere is best as it more nearly 

 represents the conditions of their original habitat. Fertilization should 

 not be attempted before the stigmas are in proper condition. This can be 

 easily recognized after some practice. The pollen should be neither too 

 fresh nor over-ripe. After applying the pollen to the stigma in many 

 cases it will be found advantageous to cover the flower with a hand- 

 glass or some similar means for a day or two to give a higher temperature 

 than that of the surrounding air. The pollen of many plants, if in good 

 condition, can be kept in small glass vessels, well corked, for several days 

 without loosing its fecundating i ower. Whether fertilization is possible 

 or not can be easily ascertained by a microscopical examination of the 

 forms of pollen grains. If their forms are fairly constant the pollen will 

 do for fertilization, but if markedly different its use for this purpose is 

 impossible, The prepotency of sex was shown by the statement that iu 

 8 cases out of 10 the female parent has the greatest influence on the 

 progeny. The staminate parent usually controls the color of the 

 offspring, and in most cases the hybrid plants have larger flowers than 

 those possessed by either parent. 



