128 
W. C. Worsdell. 
the entire habit, secondly, the function of spore-production or 
fructification, stamp this sporophyte generation as antithetic when 
compared with the so totally different and vegetative sexual 
generation. Nevertheless, the two generations are but two opposed 
and complementary phases, the two poles, the active and passive, 
vegetative and fruiting, of a single, individual life-cycle, which is a 
unity in itself. To one who clearly fathoms the real meaning of 
this antithetic alternation of generations the whole of the oppo¬ 
sition offered to it by the supporters of the “ homologous ” view seems 
utterly wasted and beside the point; it is the same as saying that 
night and day are identical; fundamentally, the two generations are 
in no other sense antithetic to one another than are the two periods 
of night and day; for different functions correspondingly different 
structures and different qualities are required, and nothing could be 
more antithetic than the respective functions of the sexual and 
sporophyte generations. 
The Fern-plant may sometimes arise from a vegetative cell of 
the prothallus instead of from the fertilised egg-cell; sporangia may 
arise on it, indicating the presence of a latent Fern-plant springing 
from vegetative tissue of the thallus; these facts cannot possibly 
disturb the antithetic relationships of Fern-plant and prothallus. 
It simply has nothing to do with the matter. Protonemal filaments 
may occasionally arise from inner stalk-cells of the Moss-sporo- 
gonium; this is due to the fact that these cells are sterilised spores 
which are merely reverting back to their primitive function; 
Pringsheim never succeeded in inducing sprouting of the superficial 
cells of the stalk, for these were the earliest to lose the reproductive 
function. 1 All these abnormal happenings, as well as those of 
apospory in Ferns, do not, to my mind, touch in any conceivable 
way, the question of alternation of antithetic generations. Those 
who believe that the facts of apogamy, for instance, prove the 
existence of an homology between the two generations, surely com¬ 
pletely misunderstand what we really mean by antithetic alternation ! 
These very interesting abnormal cases merely prove, to my mind, that 
the two generations are very intimately related (yet not homologously) 
1 It is merely the character of the individual cells or cell-groups, 
producing the apogamous or aposporous individuals, not that 
of the generations themselves, which is affected by these 
occurrences. These latter tend, on the contrary, to strengthen 
the view of antithetic alternation which could only be over¬ 
thrown if it could be demonstrated that a prothallus ever 
developed from an archegonial cell, or that a sporogonium 
could ever arise from a spore or from a chopped-up sporo- 
gonial-stalk! This has never yet been accomplished. 
