SCIENTIFIC SUMMARY. 
523 
an elaborate paper has been published by Mr. Hollard, who has traced out the 
several homologies between the brains of fishes and mammals — no easy 
matter. He states that the brain of fishes may be regarded as being made up 
of three ventricular divisions, which correspond to the three primitive cerebral 
vesicles. The anterior and posterior regions become divided into two distinct 
sections. The inferiority in the cerebral organization of the fish has reference 
to the posterior sections, the middle cerebrum or nucleus, and the anterior 
brain or the hemisphere. The middle or “ intermediate ” brain corresponds 
to the fundamental part of the nucleus of the cerebrum. The inferior lobes 
correspond to the corpora striata. The anterior lobe of the brain of fishes 
corresponds to that portion of the hemispheres which is nearest the corpora 
striata. The plates which accompany Mr. Hollard’s paper demonstrate the 
above conclusions clearly. — Yide Robins’ Journal de V Anatomic, No. 3. 
Metamorphoses of the Nematoid Worms. — MM. Yan Beneden and Leuckart, 
two of the most distinguished helminthologists of Europe, have been making 
a series of researches upon the development-history of the nematoid worms ; 
and in a memoir presented to the Belgian Academy of Sciences, they have 
announced some startling conclusions at which they have arrived. It seems, 
from their investigations, that many of the nematoidse undergo several 
distinct changes of form, which are associated by a change in the “ host ” in 
which .they live, or in the conditions under which they exist. There appears 
to be a very decided relationship between the Ascarides and the genus Oxyuris. 
It is alleged that the Ascaris nigrovenosa of the frog acquires its full sexual 
development after it has left this animal and has taken up his abode in a 
moist soil. Whilst in its parasitic form, the male sex is the only one that 
has been observed. Both males and females appear when it becomes resident 
in the soil. — Yide ISInstitut, August 1st. 
The Disease of the Silk-worm. — M. A. B4champ’s experiments and observa- 
tions on this point are of interest. He states that the disease known as 
pebrine, is due to the presence in the tissues of the animal of a number of 
dark vibratile corpuscles. The malady, he says, is not constitutional, it is 
parasitic. The vibratile corpuscles are only a pathognomonic sign, and are a 
pathologic condition. The corpuscles are the producing cause of the affection. 
M. B4champ states, that when the black spots with which the affected silk 
worms are covered, are washed or brushed, numbers of those vibratile cor- 
puscles are found. He formulates the following conclusions : — (1) The cor- 
puscles are situate on the external surface of the egg ; the more the latter is 
washed, the less the quantity of corpuscles becomes. (2) Larvse, which have just 
left the egg, may contain these corpuscles ; but washing removes them. (3) 
The larvse spotted with pebrine may have no corpuscles in their tissue, although 
a washing may discover several of them on the outer surface. (4) Even in 
larvse in which there are no spots, there may be the characteristic corpuscles of 
pebrine on the surface, but none in the tissues. Hence, says M. Bechamp, 
the malady is one derived from without ; it is not like the corpuscles of pus, 
cancer, or tubercle, but is, in fact, a vegetable cellule. — Yide Comptes Bendus , 
August 13th. 
The Sarcodic Tissue of the Sponge. — It is generally stated, says M. Grave, 
in a paper read before the French Academy, on the 9th of July, that the 
soft tissue of the sponge is a gelatinous amorphous mass. But far from 
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