314 
NOTES AND MEMORANDA. 
FMontlily Microscof)ical 
L Journal, May 1, 1869. 
two glands or two diiTerent parts of the same organ— the development 
takes place in the germigenous portion; in all the higher animals it 
takes place in the ovarian tubes, of which the Grafian vesicles are a 
fraction. In these organs there is a liquid, which the author calls a 
protoplasmatic liquid, which holds in suspension nuclei with nucleoli. 
The nuclei divide, and each one accumulates round it part of the 
common protoplasm ; and when thus the cellular layers are separated 
from each other, the cell-egg is completed. There is no vitelline layer 
in the commencement of the egg, but only this protoplasmic envelope 
round the nucleus. From these facts the author draws the conclu- 
sion that it is not the vesicle of Purkinje which is formed in the first 
place ; but these vesicles and the protoplasm are formed simultaneously, 
and the latter condenses later round each nucleus. Among the points 
of interest in this memoir of M. Van Beneden is the discovery of an 
actual micro]pyle in the ovum of the cow. — See L'Institut, March 31st. 
Mechanism of Fecundation in Lepidoptera. — Under this title a very 
interesting paper by M. Balbiani appears in the ^Comptes Bendiis,' 
March 29th. The author describes the reproductive apparatus in 
much detail, and he points out the existence, of a peculiar depu- 
rating function on the part of the copulative pouch. He believes 
that the structures he describes are used to separate the zoosperms 
from foreign bodies which they may become associated with, and which 
would prove injurious to the ovum. 
Function of the Latex on the White Mulberry. — The above-mentioned 
' Compte Bendu ' contains also a valuable paper by M. Faivre on this 
subject. The author concludes that the latex is not simply an excre- 
tion ; it is the alimentary matter of the plant. 
NOTES AND MEMOKANDA. 
Eoss's Eeversible Compressorinin for High and Low Powers.— 
This instrument consists of a metal frame A A, in one end of which 
there is a quick-acting screw B, 
with milled head C, which drives 
forward a fork-piece with wedge- 
shaped sides D ; this fork- piece 
moves on the raised sides (also 
wedge-shaped) of a brass plate E, 
kept separated from the plate H 
of the metal frame A A by two 
springs between them, so that, 
when the screw B is moved for- 
ward, the brass plate E, by the 
action of the wedge D, is made to approach to the metal plate H of 
the frame A A. In each of these plates, but on opposite sides, is 
