i879-] 
Notes. 
703 
M. Leon Fournol, in the “ Journal d’Hygiene,” gives an 
interesting summary of our present knowledge concerning poi- 
sonous fishes, which appear to be a source of grave danger. 
We may trace here four distinct cases. There are fishes per- 
fectly harmless at some seasons of the year, but poisonous at 
others. This has been observed in Japan with the common 
salmon, the bonito, and the albicore. The symptoms generally 
resemble those caused by the ingestion of corrupted meat, and 
though alarming are rarely fatal. Other fishes, such as 
Lethrinus nambo , are wholesome when young, but become poi- 
sonous when they reach a certain growth. Other aquatic 
animals — the conger, the pike, the barbel, the prawn, and the 
mussel — are occasionally and capriciously poisonous. In one 
instance a number of persons who had partaken of the spawn of 
a large barbel experienced very severe symptoms of poisoning, 
whilst one of the party who had not eaten any of the spawn 
escaped. The liver and the head in several species of fish 
inhabiting different parts of the world are found exceptionally 
dangerous. The occasionally poisonous action of mussels, 
oysters, &c., is ascribed by eminent authorities to their having 
eaten the eggs of the star-fish, which are occasionally found in 
these mollusks on dissection, and which, when handled, produce 
violent cutaneous irritation. Other fishes appear to be poisonous 
at all times and under all circumstances. Prudence dictates 
that the roe, liver, &c., of all unknown fishes should be carefully 
avoided, and it is very doubtful whether aquatic species of 
animals too small to admit of the removal of the alimentary 
canal, with its possible contents, should be eaten at all. The 
entire question offers a splendid field for research, both biological 
and chemical. 
M. J. Kiinckel has published in the “ Comptes Rendus ” the 
results of an extended series of researches on the nervous system 
of the Diptera. He recognises in some cases an absolute cen- 
tralisation, or an extreme dispersion of the nervous centres, with 
the most varied intermediate arrangements, but each family has 
its nervous system constructed upon a peculiar and invariable 
plan. The number of nervous centres varies, however, gradually 
from one family to another. 
M. E. Brandt has laid before the Academy of Sciences certain 
interesting results concerning the nervous system of insects. 
He finds that in the genera Rhizotrogus, Stylops, and Hydro- 
metra the subcesophagian ganglion is not separated from the 
following ganglia, as has been supposed to be the case in all 
insects. Hence this character can no longer serve to distinguish 
the nervous system of insects from that of the other Arthropoda. 
The pedunculated bodies of Dujardin, or the cerebral circum- 
volutions, are not only met with in some insects, but in all. In 
some insects a difference in the development of these convolu- 
tions is found, even among different individuals of the same 
2 Y 2 
