Books and Current Literature. 101 



graft hybrids between the tomato and black nightshade. Shoots 

 arising from calhised regions in which the tissues of stock and 

 cion had grown together showed a Mosaic or a fusion of the qual- 

 ities of the two parental species. 



Five distinct forms were easily made out, which the author 

 designated as Solarium tubingense, S. Gaertnerianum, S. Koelreu- 

 terianum, S. Darwinianum, and 5. proteus. When seeds produced 

 by these various forms were sown, the progeny of any type was 

 composed coinpletely of plants almost identical with the parent- 

 al species which the graft hybrid resembled most closely. The 

 second generation was thus composed of tomato plants from 

 some of the hybrids and nightshade from others. 



The plants derived in this manner, however, were not en- 

 tirely like the nightshade and tomato which were originally 

 united, but displayed some modified characters, which are possi- 

 bly beyond the range of fluctuating variability. 



While it is clear that no fixed hybrids were produced by 

 Winkler, yet the end result is similar to that of Mendeliaa 

 crosses. The final decision as to whether or not the types pro- 

 duced are to be regarded as true graft hybrids, must rest upon the 

 results of cytological investigations now being carried out by 

 Winkler. 



Prof. Bateson's treatise on "Mendel's Principles of Hered- 

 ity" recently re-issued by G. P. Putnam's Sons of New York, 

 has been received. The accumulation of information bearing 

 upon alternation of inheritance and segregation of characters has 

 now reached a point where this book of four hundred pages is 

 necessary to set forth some of the more important experimental 

 results and conclusions. To those who question the validity of 

 the Mendelian ideas and doubt their capacity for wide appli- 

 cation, the list of structural characters in which studies hav^ 

 been made, will be an "eyeopener." 



The development of modified ideas as to the behavior of 

 "unit characters" and a better understanding of dominance as a 

 phenomenon of heredity, has widened the usefulness of the 

 Mendelian theories, and given all workers definite and exact 

 methods by which both theoretical and experimental research 

 may be carried forward profitably. 



