1894, | Recent Literature. 501 
back into normal. In the concluding section, all life phenomena are 
referred back to chemical processes. 
Under the title Dynamics in Evolution, Professor Ryder reiterates 
his mechanical ideas, explains the changes in form of an ameba by 
differences of surface tension and this again by chemical action. He 
has no sympathy with “ biophores ” and “ gemmules ” and thinks that 
experimental investigation in embryology will make no firm progress 
until the mischievous influences of those speculations which deal with 
“germ plasms” and the like have been entirely eradicated from the 
present generation. 
Dr. Watase, treating of the nature of cell organization, thinks it 
not improbable that in the cell we have a symbiotic structure, the 
nucleus and the cytoplasm living together in a way analogous to that 
presented by the alge and the fungus in the lichen. Professor Whit- 
man’s lecture on the Inadequacy of the Cell Theory of Development 
is most suggesitve, but is so condensed as to be beyond any adequate 
abstract. In a word it is that in our discussions of the cell as a unit, 
especially in the experimental embryological researches, the tendency 
has been to regard the cell as all in all, while in reality the whole 
organism is the entirety. 
The thesis which Dr. Howard Ayers maintains in his study of the 
Pacific Hagfish Bdellostoma dombeyi, are that this form is very varia- 
ble and that the number of gill slits cannot be used as a criterion for 
separating genera and species; further that it is a primitive rather 
than a degenerate type; and lastly that a study of the ears of this 
animal show that these organs cannot be considered as organs of equi- 
libration. 
The next two lectures touch upon the Botanical side. Dr. W. P. 
Wilson discusses the influence of external conditions on plant life and 
presents an essay which goes far toward showing that such striking 
acquired characters as the knees of the bald cypress are not inherited 
but will disappear in a single generation with changed conditions, and 
that the same is true of the remarkable roots of the Black mangrove 
of Tropical America. The other botanical lecture, by Professor J. 
Muirhead Macfarlane, treats of irrito-contractility in plants, in which 
he shows that this phenomenon is much more common than is ordina- 
rily supposed, but that there is usually a latent period and that in 
many instances the stimulus has to be repeated before marked mani- 
festations are produced. 
The last lecture—upon the Marine Biological Stations of Europe by 
Dr. Bashford Deane—is familiar to our readers. The volume closes 
