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conclusions have a special embryological interest. He has found that (as 
pointed out by Quatrefages in other animals) the disappearance of the ger- 
minal vesicle takes place independently of fecundation. The other points 
are as follows : — 1. The ovarian ovum has no vitelline membrane ; 2. The 
embryos adhere to one another on leaving the egg ; and 3. The ovum presents 
a yei'minal fossa which is not an aperture, but which the author compares to 
the micropyle. — Vide H Institut, August 28. 
How to detect the Silkworm, Malady. — M. Pasteur’s method, which con- 
sisted in selecting a number of worms, pounding them in a mortar, and then 
submitting the mass to the microscope, was neither simple nor economical. 
The method which M. Balbiani suggested recently seems a better one. When 
in the chrysalis state, a very small portion of the projecting process which re- 
present the future wing is snipped off with a pair of scissors, and is placed 
under the microscope ; if now the larva be diseased, the peculiar pebrine 
corpuscles can be distinctly seen. The advantage of M. Balbiani’s method is 
that it does not involve the death or injury of the silkworm. 
Reproduction of Limbs in the Axolotl. — The axolotls (specimens of which 
may now be seen at the Zoological Gardens in Regent’s Park) have lately 
formed the subject of experiments by M. Dumeril. M.Dumeril found that in 
these animals, as in the newt, there is no regeneration of amputated limbs 
unless the basilar segment (scapular or ilium) is left untouched by the knife. 
M. Vulpian’s recent observations, recorded to the Societe Philomathique, also 
prove the fact of regeneration. M. Vulpian finds that when a number of 
axolotls are together, it not unfrequently happens that, from bites and other 
injuries, portions of the young limbs are destroyed. The consequence of this 
is not simply the reproduction of the part destroyed, but the formation of 
even a greater number of parts than were normally present before the injury. 
This, he says, is the reason why we so often find specimens of axolotls whose 
fore-limbs have five or six digits, instead of four, and whose hind ones have 
as many as six or seven extremities, instead of five. 
