V. H. Blackman. 
to i 
result was that with some crosses only one kind of hybrid was 
produced, while from others several forms arose. Some of the 
forms remained constant in the second generation, while others 
showed a separation of characters; while, exceptionally, there were 
produced from one and the same cross, forms, of which were some 
schizogonous and some homoiogonious, in relation to the same pair 
of characters. 
Tschermak ( 1900 , 1901 ) from a large series of experiments, 
makes clear the existence of homiogonous characters in Peas and 
Beans, and also confirms to a great extent the work of Mendel, but 
finds a few exceptions among Peas, even to the dominance of such 
characters as yellowness of cotyledon and smoothness of seed coat. 
It is clear from the observations of Correns, Tschermak and 
De Vries that recent work, while confirming and extending the appli¬ 
cation of the laws enunciated by Mendel, has tended to show that 
these laws are only special cases of more general ones yet to be 
discovered. The value of his observations is however not lessened, 
and his work remains a pattern for all future researches on 
hybridization. 
To him (as pointed out earlier), we largely owe the important 
conception of unit characters, a conception which recent work has done 
much to confirm, for it is clear that a consideration of schizogonous 
pairs of characters, whether homodynamic or heterodynamic, in 
which the characters (or rather their “ Anlagen ”)* are separated in 
the gametes, suggests that they retain their separate entities in the 
development of the individual, but react upon one another/ and 
affect the development of the respective characters to a various 
extent (as in homodynamic pairs), sometimes to the point of the 
complete extinction of one (as in heterodynamic pairs). It may be 
further said that Mendel’s work, and all the recent work on hybrids, 
seems to point to a theory of heredity of the type of Darwin’s 
Pangenesis in the form lately put forward by De Vries. 
Weldon ( 1902 ), after pointing out the numerous exceptions to 
the law of dominance and that of Mendel, both in hybrids generally 
and Pea races themselves, puts forward the view that the behaviour 
of the character of a hybrid is dependent on the ancestry of the 
parents, as would be suggested by the Galton law of blended 
inheritance. Standfuss, from observations on butterfly hybrids, and 
De Vries (1900 b) from observations on various plant hybrids, have 
* By “ Anlagen ” we understand the germ or apparatus (whatever 
tiinay be) which brings about the development of that 
character. 
