2i6 PLANT HYBRIDIZATION BEFORE MENDEL 



supporter of Darwin. Focke was the founder of the Natural His- 

 tory Society in Bremen (1864), and until 1895 remained the editor 

 of its "Transactions." His best-known botanical contribution is 

 his "Pflanzenmischlinge" (1881), besides which he published in 

 1877 a "Synopsis Ruborum Germaniae" and "Species Ruborum, 

 Monographia, Generis Rubi Prodromus," published in the Biblio- 

 theka Botanica, 1914. He is reported as having contributed greatly 

 as a physician to the development of medical science in Bremen. 

 On his eightieth birthday, a "Festheft" appeared in his honor in 

 the Abhandlungen of the Natural History Society of Bremen, 

 Vol. 23. 



28. The Hoffman Mendel Citations. 



Aside from Focke's the only other reference to Mendel before 

 1900 is made by Hermann Hoffmann, "Untersuchungen zur Bes- 

 timmung des Werthes von Species and Varietat," at Giessen, 1869, 

 referred to by R. C. Punnett, in Nature, Vol. 116, p. 606, Octo- 

 ber 24, 1925. 



Hoffman was Professor of Botany at Giessen, and became en- 

 gaged, from 1855, upon experiments with varieties of garden 

 beans, the results of which were reported in the Botanische Zei- 

 tung for 1862. As a result of these experiments it was found that 

 small variations which appeared in the seeds did not lead to the 

 formation of permanent new forms, but rather, on continued 

 (isolated) culture, reverted every tim^e immediately to the funda- 

 mental form. (p. 1.) The experiments were continued in the light 

 of Darwin's "Origin of Species" which appeared in 1859, the 

 object of the experiments being to determine whether new species 

 and varieties continue to originate from natural selection, or 

 through physical and similar influences. Hoffmann's contribution 

 of 1869 is therefore a study chiefly of variation, the question 

 being as to whether "varieties" can be "fixed." 



The chief portion of the paper (pp. 47-80), is devoted to the 

 author's selection experiments with varieties of Phaseolus vul- 

 garis, x^lthough some crossing was attempted, the experiments are 

 almost entirely in selection for color in the seed-coat. The ultimate 

 aim of the investigation was the determination of the value of 

 species and varieties, and the fixability of varieties. Hoffmann 

 concludes (pp. 169-71) that certain varieties of Phaseolus vulgaris 



