470 THE AMERICAN NATURALIST. 
body of Bethe’s paper, they are found to be not very convin- 
cing. In his third study ! on the central nervous system of the 
crab (Carcinus), he discusses the question of fibrillar continuity 
in the neuropile and states that in this animal he has never 
been able to discover continuity between the fibrils of two 
neurones, though he has some evidence from the leech that 
he believes supports this idea and that he proposes to publish 
later. Sucha statement of lack of conclusive evidence on an 
all-important point can scarcely be called a confirmation of the 
*idea of continuity. 
These seem to me the most important contributions made 
against the neurone theory, and I believe it must be admitted 
they are not fatal objections. In no case has any one made 
observations which show that each neurone does not begin as 
an essentially independent cell, suffering eventually remarkable 
modifications, but still retaining its character as a single cell. 
In no case has any one shown that the individuality of the 
adult neurone, as seen in the degeneration and regeneration of 
its parts, has suffered any reduction as compared with that of 
the simple cell from which it came. It seems to me, therefore, 
that the neurone theory is still intact, and that what has been 
shown by this new work is that the interior of a neurone has a 
most delicate and complicated fibrillar structure, which possibly 
is a means of welding together adult neurones much more 
closely than has been generally admitted. But of this we 
have as yet no adequate proof. 
1 Bethe, Albrecht.. Das Centralnervensystem von Carcinus Maenas. Ein 
anatomisch-physiologisch Versuch. II. Theil. (3. Mittheilung). Archiv für mikro- 
scop. Anat. Bd. li, pp. 382-452, Taf. XVI-XVII. 1898. 
