ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
613 
Although the necessary embryological data are here wanting, it is not 
likely that the nerve-ring was originally mesoblastic. Similar regenera- 
tive experiments on Lumbriculus led to similar results. 
The author’s conclusion is that the conception of the parallelism of 
ontogeny and regeneration must undergo fundamental modification, and 
points out the danger of filling up gaps in embryological observations 
with inferences drawn from processes of regeneration. 
The Origin of Species.* — M. Lavocat in a lengthy paper opposes 
the current doctrine of evolution, which he terms “ the theory of trans- 
formations.” He asserts that no transition form between two species 
has been found, either fossil or living, and that variability is so limited 
as to be only able to produce varieties or races and not species. The 
author’s own theory is that “ every species has had a special and distinct 
origin ; that in every case forms primitively imperfect have gradually 
developed; and that every species has proceeded not from a single 
centre, but from every region where circumstances were favourable for 
its formation and development.”! The question of the first origin of 
these primitive species is said to be unanswerable. 
#. Histology. 
Recent Views on Protoplasm. j — Enquiries are often made for some 
useful critical summary of recent speculations on protoplasm. This 
appears to have been given by Prof. W. A. Has well, who took “ recent 
views on the structure of protoplasm and the significance of the various 
parts of the cell ” as part of the subject of his presidential address to 
the Linnean Society of New South Wales. He thinks that some definite 
progress has undoubtedly been made of late in our knowledge of the 
relative importance of the different parts of the cell. A serious assault 
has been made on the predominance of the nucleus. The centrosomes 
or attraction spheres, first discovered by E. van Beneden, appear to be 
independent centres of activity, and they, with the spindle-fibres that 
proceed from them, appear to be of importance in cell-division ; indeed, 
according to Rabl and others, they form the actual vital parts of the cell. 
We commend the address to the enquirers to whom we have referred. 
The Cell.t — Prof. O. Hertwig’s admirable book should have found 
earlier notice in our pages. It contains in compact form an account of 
the more important facts in regard to the cell, stated with the author’s 
wonted clearness and is well illustrated. A short historical chapter is 
followed by a discussion of the structure, functions, and chemistry of 
the cell. The animal and the vegetable cell receive parallel treatment, 
and throughout the book the relation of the established facts to general 
biological conclusions is kept in the foreground. As the author admits in 
the preface, his own views are emphasized. This emphasis is natural, for 
Prof. 0. Hertwig’s contributions to cellular biology have been numerous 
and of great importance, but we are inclined to think that a little more 
space might have been found for the conclusions of other workers. The 
second volume will treat of tissues. 
* Mem. Acad. Sci. Nat. Toulouse, iv. (1892) pp. 44-65. 
f Proc. Linn. Soc. N.S.W., vii. (1893) pp. 673-85. 
X O. Hertwig, ‘ Die Zelle und die Gewebe. Grundziige der allgemeinen Anatomie 
und Pliysiologie,’ Theil i., 8vo, Jena, 1892, 296 pp., 168 figs. 
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