414 
Dl D. FEN YES 
rage of the inheritance and the extremes of the 
atavism or reversion and variation by means of 
the possible combinations of the genes or factors 
are determined finally by the proportion of the 
corresponding chances of probability respectively. 
It is doubtful if we could come nearer our aim, the knowledge of the 
truth, when we search for the number of the pairs of genes or factors, and 
it is a question whether we could count the number of the drops which 
make the ocean. Would the way to the knowledge of facts and causes of 
facts not be shorter and surer, if, instead of the prospectless guesses, we 
were to try, by means of the study of the proportions of the properties of 
the ancestors, to tear off the dense veil of the problem of heredity? 
Suppose, that there is no relationship between white pure 
breed and black pure breed, viz., these two breeds moved themselves far 
from the common ancestor ; when crossed, there is, consequently, no domi¬ 
nance, no uniformity. The hybrid offspring will represent an intermediate 
series varying in accordance with the binomial rule, and can be classed 
under three natural groups, viz., (1) patroklin type, in appearance % white -f 
% black ; (2) the average, in appearance y 2 white + % black (grey) ; 
(8) matroklin type, in appearance % white -|- % black. The numerical 
ratio of the three types is 1:2:1. (It should be stated at the outset, that 
the goneoklin extremes do not breed like % bred, or % bred hybrids re¬ 
spectively, but, as regards heredity, they only slightly deviate from the 
average, which is, considering the above explained relation between the 
properties of the individual and that of those of the ancestry, self evident.) 
The succeeding possible matings belong to three chief classes, viz., (1) inter 
se matings between full brothers and sisters ; (2) matings between the 
offspring of different generations ; (8) consequent back-crossings of the 
hybrid stock to one of the pure-bred ancestors. There are, under each of 
these chief classes, three possible sub-classes again, according as offspring 
of the (1) patroklin, (2) average, or (8) matroklin type, respectively, are used. 
Naturally, in all the above cases, regularity can be observed, but on 
the present occasion I do not intend to deal with them. I note only, for 
their general characterizing, that in the cases, when offspring of the same 
generation are mated inter se, the type through the series of succeeding 
generations gradually becomes uniform about an average, which is inter¬ 
mediate between the two ancestral breeds; when goneoklin selection is 
employed, the average declines to a certain limit towards the corresponding 
side. In the cases of back-crossing, i. e., the consequent matings of the 
average-produce and one of the pure ancestral breeds, the equalization 
approaches and reaches the type of the pure ancestral breed through arith- 
