12 THE ORCHID REVIEW. [JANUARY, I9i0. 
hybridist, for having first raised his hybrids he then carefully isolated and 
self-fertilised them, in order to trace the inheritance of characters through 
succeeding generations. The hybridist has different objects in view. He 
continues to cross promising individuals in the hope of obtaining further 
improvements, but both methods afford an opportunity for dissociation of 
the mixed character, and the rearrangement of such characters as are 
present. It may perhaps be said that the hybridist only adopts the 
Mendelian method when having obtained a suitable hybrid he attempts to 
fix its characters so as to ensure its breeding true from seed. And this he 
was doing long before Mendel’s experiments were made, and it is doubtful 
whether the latter’s results with Peas would help him much in working 
with other subjects, because their behaviour would have to be ascertained 
by experiment. 
But to the systematist the discovery of the dissociation of specific 
character in secondary hybrids should be of the greatest use. A good many 
plants have been described as species which are now known to be of hybrid 
origin, but it is frequently impossible to ascertain this by examination. 
Sterility of the anthers might be detected, but a good many hybrids are 
known to be fully fertile, and such plants are liable to be described as 
species if their history is unknown, at all events if they appear to be 
distinct. Now species are known to reproduce themselves true from 
seed, so that if any suspected plant on being self-fertilised showed 
dissociation of character its mixed origin would be at once revealed. It 
is probably not an unfailing test, because some hybrids are said to reproduce 
themselves true from seed, but the probability is that dissociation would 
manifest itself in the great majority of cases. -In an experiment of this 
kind, of course, care would have to be taken to prevent any possibility of 
further crossing. 
The reason for this dissociation is to be sought in what may be termed 
the permanence of specific character. A species reproduces itself true from 
generation to generation, its characters having become fixed under normal 
conditions through having followed the same cycle of existence through 
numerous successive generations. Different species show different phases 
of development according to the remoteness of their relationship, and the 
different phases through which they have passed since diverging from the 
common starting point. Hybrids differ from pure species in the fact that 
they combine different hereditary tendencies, and in their development they 
necessarily follow a different scheme from that of either parent. Hybrids 
thus combine conflicting elements, the result being a struggle for ascendancy 
and a compromise, which may be of a more or less temporary nature, the 
conflicting elements re-separating themselves at the earliest opportunity. 
These facts were clearly appreciated by Mendel, who pointed out that if 
