348 Blackman.— On the Fertilization 3 Alternation of 
It must be pointed out in relation to the observations of Cornu (12), 
Brefeld (10), Plowright (42), Sapin-Troufify (48), and others on the ger- 
mination of the spermatia in nutritive solutions, that a complete absence 
of power of vegetative development is not a necessary character of male 
cells, as is shown by the well-known cases of the potential gametes of some 
algae which can develop either sexually or asexually. It must also be 
remembered that nutritive solutions are a highly artificial condition for the 
reproductive cells of such obligate parasites as the Uredineae ; it is difficult 
to understand how the spermatia could act in nature as infecting organs 
(conidia) unless they are able to germinate in water like the other spore- 
forms of the group. Their appearance at about the same time as the 
aecidiospores is another argument against their conidial nature (as well 
as an argument in favour of their sexual nature), for, in the presence of 
such very effective infecting organs as the aecidiospores are known to be, 
there would seem to be absolutely no need for the production of conidia 
so structurally ill-equipped for directly carrying on the life-cycle as are 
the spermatia. The fact that most of the spermatia in the forms investi- 
gated are found to be disorganized soon after they are shed, and that 
rarely in G. clavariaeforme some of them degenerate while still in the 
spermogonium, is evidence against the conidial view and in favour of the 
view that they are abortive male cells. 
There is of course a view which might be suggested, that the spermatia 
are degenerate conidia which have ceased to have any function. Such 
a view, however, may certainly be dismissed, for it is difficult to imagine 
the conditions in which the conidia would cease to be of value, and still 
more difficult to imagine a process of degeneration which brought about 
a reduction of the cytoplasmic portion of the cell, but left the nucleus 
untouched. 
That the spermatia, though perfectly functionless, should still be pro- 
duced by the majority of forms and in such great abundance is certainly 
a very striking phenomenon 1 . A somewhat similar process, apparently 
equally wasteful, is to be observed in certain animals, as in the gasteropod, 
Paludina , where two sorts of spermatozoa, normal and giant ones, are 
constantly produced, although the smaller ones only are functional. 
The similarity of the spermogonia of the Uredineae to those of 
Collema , in which the earlier observations by Stahl on the fertilizing 
action of the spermatia have of late years been confirmed by Baur (5), 
is additional confirmation of the view that the spermatia in the Rusts are 
male cells. 
It is true that Moller has shown that in certain cases the spermatia 
Even when the aecidinm is dropped out of the life-history the spermogonium sometimes still 
remains as the first structure to be developed on the mycelium which arises from the sporidium, being 
later followed by uredospores or teleutospores ; e. g. in the so-called brachy- forms. 
