POLYMORPHISM. 185 
without, among the seed which is sown, but that has been 
antil now quite disregarded. It is of great importance in 
practice, but in truth, for our present purpose, synonymous with 
what we have already written. Those learned in the science of 
this kind of culture lay great stress on its importance, and 
many apparatuses have been constructed, called “ purely cultivat- 
ing machines,” for the purpose of destroying the spores which 
are contained in the substratum, and preventing the intrusion of 
those from without. The mixture in the seed which is sown 
has of course not been obviated. These machines may, perhaps, 
in every other respect, fulfil their purpose, but they cannot 
change the form of the question, and the most ingeniously con- 
structed apparatus cannot replace the attention and intellect of 
the observer. * 
Two distinct kinds of phenomena have been grouped under 
the term “polymorphy.”’ In one series two or more forms of 
fruit occur consecutively or simultaneously on the same indi- 
vidual, and in the other two or more forms appear on a dif- 
ferent mycelium, on a different part of the same plant, or ona 
matrix wholly distinct and different ; in the latter case the con- 
nection being attested or suspected circumstantially, in the former 
proved by the method suggested by De Bary. It will at once be 
conceded that in cases where actual growth and development 
substantiate the facts the polymorphy is undoubted, whilst in the 
other series it can at best be little more than suspected. We 
will endeavour to illustrate both these series by examples. 
One of the first and earliest suspected cases of dualism, which 
long puzzled the older mycologists, was observed amongst the 
Uredines, and many years ago it was held that there must be some 
mysterious association between the “red rust” (Trichobasis ruligo 
vera) of wheat and grasses and the “corn mildew” (Puccinia 
* The method pursued by Messrs. Berkeley and Ioffinann of surrounding the 
drop of fluid, in which a definite number of spores or yeast globules had been 
placed, with a pellicle of air, into which the germinating threads might pass 
and fructify, is perhaps the most satisfactory that has been adopted, though it 
requires nice manipulation. If carefully managed, the result is irrefragable, 
though doubts have been cast, without any reason, on their observations. 
