SCIENTIFIC SUMMARY. 
Ill 
The author, like Kleinenberg, has observed an agglomeration of cells of 
ectodermic origin, but regards them merely as embryonic cells, serving to 
reproduce different ectodermic elements. One of these cells increases, and 
its nucleus is converted into a germinal vesicle ; while at the same time the 
peripheral elements of the mass separate, forming a row of cells with very 
small refractive granules, and the central cells unite with each other and 
with the enlarged cell, forming a common plasmodium sprinkled with 
numerous nuclei. The germinal vesicle is degraded and disappears entirely ; 
the nuclei of the central cells increase a little in volume and degenerate into 
fatty bodies, and some of them divide. These are probably Kleinenberg’s 
pseudo-cells. The peripheral elements of the mass sprinkled with chitinous 
granules form the envelope of the ovum. M. Korotneff concludes that 
Kleinenberg mistook these peripheral elements for a blastoderm, and the 
mass of central cells for the result of a true segmentation. — Comptes Rendus , 
September 9, 1878. 
The Buzzing of Insects. — M. Jousset de Bellesme objects to the theory of 
the cause of buzzing in insects proposed by M. Perez as noticed in our last 
number. He remarks that all insects in which the wings make more than 
eighty vibrations per second emit a perceptible sound which is suppressed by 
the removal of the wings. The diptera and hymenoptera emit two sounds — 
that just mentioned, which is deep ; and another sharper sound, generally 
the octave of the former. This is the essential characteristic of buzzing. 
When the wing3 are cut off a Volucella or humble-bee, the deep sound is 
abolished, but the sharper one persists. The former is therefore produced by 
the wing, while the latter is independent of it. 
M. de Bellesme agrees with M. Perez that this sound is not connected 
with the passage of air through the thoracic stigmata, and he seeks its cause 
in the mechanism by which the wing is set in motion. He says that in 
buzzing insects the muscles of flight are not inserted directly upon the wing, 
but upon the pieces of the thorax which carry it, and that it is the move- 
ment of these that causes that of the wing. The thorax, therefore, undergoes 
continual changes of form under the contraction of these motor muscles. In 
repose a section of this region represents a vertically elongated ellipse, which 
the action of the muscles converts into a horizontally elongated ellipse. The 
entire thorax, therefore, vibrates successively in the direction of its two dia- 
meters ; and, as the muscles are very powerful, the vibratory movement is 
very intense, and the thorax constitutes a vibrating body which acts directly 
upon the surrounding air. The thoracic sound is higher after the wings are 
cut away. This is because during flight the resistance of air acting upon the 
wings diminishes the velocity of contraction of the muscles. By attaching 
a style to the upper wail of the thorax after the removal of the wings the 
author was enabled to inscribe these vibrations, and obtained traces in 
which the number of vibrations corresponded exactly to the sound produced. 
— Comptes Rendus, October 7, 1878. 
The Poison Glands of the Centipedes. — It has long been known that the 
Chilopod Myriopoda, commonly known as Centipedes, which are carnivorous 
in their habits, kill their prey by a poison injected at the first bite of their 
formidable nippers. The seat of the glands secreting the poisonous fluid was, 
however, unknown, the organs formerly supposed to secrete the venom being 
