116 Discussion on “ Alternation of Generations 
a freed fertilised egg-cell develop into a prothallus, and an im¬ 
prisoned spore giving rise to a fern-plant, yet some deviations of 
development might be obtained which would furnish evidence in 
support or in contradiction of Dr. Lang’s hypothesis. 
Some of them had perhaps during the last twenty years or so 
been over-impressed by the magnificent results obtained through 
the application of the phylogenetic method to morphology, in the 
light of the immensely increased detailed and accurate knowledge 
of structure that had accumulated. As a result some of them 
had perhaps been tempted to overlook those fundamental physio¬ 
logical factors—no doubt, in their ultimate analysis, physical 
and chemical factors—under which an organism actually develops 
in its ontogeny, and which no doubt played an essential 
part in determining the form and structure of that organism, as 
well as the formation of its reproductive cells. The epoch-making 
work of Klebs, on the side of discovering the factors which actually 
determined the formation of different kinds of reproductive cells in 
the Algae and Fungi, remained the nearest approach to an under¬ 
standing of that part of the problem. For the rest we knew next to 
nothing of such factors and of their relation to heredity and to 
adaptation. His own conception, not by any means an original 
one, was that while the development of the lower Thallophyta was 
very largely controlled by external conditions, working of course 
upon, and necessarily modified by, the specific material furnished 
by the protoplasm of the species, in other words on the “ specific 
cell,” the higher they went in the plant series, the more the mor¬ 
phogenetic stimuli became internal, so that each stage in the 
ontogeny came to he determined by the preceding stage rather 
than by external conditions. With that general conception he 
imagined Dr. Lang would agree. Then came what seemed to him 
the fundamental point raised by the new hypothesis. When the 
higher plant, in which a regular alternation of generations was 
established, returned to the unicellular condition, to the condition 
of the spore or of the zygote, how far did it become emancipated, 
so to speak, from this series of ontogenetic stimuli? In other 
words how far did it become capable of responding in a fundamental 
way, like its remote ancestors the unicellular Algag, to environ¬ 
mental influences ? This seemed to him the essence of the 
problem which the future had to solve. 
Dr. Lang, in replying, said that he had listened with great 
interest to the various views that had been put forward that night. 
There would be very great difficulty in making an adequate reply 
because the remarks that had been made were made from the 
phylogenetic standpoint of the old anthithetic and homologous 
theories of alternation, rather than from the ontogenetic stand¬ 
point which he had adopted. He himself had experienced 
10.15 difficulty in “thinking ontogenetically,” if he might so express 
it, on this topic. He was somewhat disappointed that almost 
every speaker in discussing the paper had departed at once from the 
ontogenetic standpoint. He felt sure that the two ways of looking 
at the phenomena ought to be kept apart if progress were to be 
made. 
[The Meeting was then adjourned.'] 
R. Madley, Steam Printer, 151, Whitfield Street, London, W, 
