PROGRESS OP MICROSCOPICAL SCIENCE. 
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One set of medullated fibres divided dichotomously in tlieir passage to 
the follicular layer at the periphery, and there formed a network of 
fine non-medullated fibres, constituting a plexus around the follicle ; 
another set formed a coarsely meshed arrangement around the vessels. 
The peripheral layer of the membrana granulosa in large follicles is 
surrounded by a fine network of nerve-fibres. The author asserts that 
he has seen fine branches proceed to the nuclei of the cells of the 
membrana granulosa. 
Researches on the Acarians. — ‘Nature’ (June 14) says that M. 
Meguin has lately been making important researches on Acarians, and 
on that strange asexual form called Hypopes, a form which is not 
absolutely necessary for reproduction, but which seems to occur under 
certain biological conditions, for the indefinite conservation of the 
species. In the aerial reservoirs of birds, especially Gallinacese, there 
breeds an inoffensive species, which M. Meguin calls Kytodites glaber, 
which sends colonies even into the bronchial branches, and into the 
marrowless bones of the limbs in communication with the air-vessels 
in birds. Another harmless acarian is found in the cellular tissue of 
birds living and dying there, and persisting after death, surrounded 
by a calcareous tubercle. A third species, which lives normally 
between the barbs of the feathers, produces at the time of moulting, 
and in the skin of the birds, especially domestic and wild pigeons, a 
hypopial vermiform nymph. Without this precaution of nature, the 
species would be annihilated, by reason of the fall of the feathers in 
the moulting season. . 
The Ending of Nerves in Tendon. — Herr Rollet has contributed a 
paper on the above to the ‘ Wiener. Acad. Sitzungsbericht ’ (vol. 
lxxiii.). He investigated the mode of termination of the nerves in 
the tendon of the sterno-radial muscle in frogs at its insertion into 
the upper arm. The agent employed to treat the tendon with was a 
half per cent, solution of perosmic acid, followed by hydrochloric acid 
(1 in 1000). A plexus of medullated nerve-fibres exists and ends 
within the tendon. The nerves divide dichotomously and end in 
peculiar structures, having much resemblance to the end plates of 
muscle. From the fact that no reflex action could be discharged from 
this tendon, it seems probable that the direction of the motion in the 
nerve is centrifugal, and not centripetal. 
The Structure and Origin of Serpentine. — The Rev. T. G. Bonney, 
who lately read (May 23) a paper before the Geological Society on 
the Serpentine of the Lizard district, discussed the question of its 
origin at some length, calling attention in this relation to a structure 
commonly seen, which appeared to be a true “ fluidal structure.” He 
then described the result of microscopic examination of many speci- 
mens of the Lizard and some other serpentines. Commencing with 
slightly altered lherzolite (from the Ariege), he traced the change 
through the older gabbro of Coverack to the serpentine rock of that 
place, which contains a large quantity of unaltered olivine ; and so to 
other serpentines in which the olivine is quite replaced by the mineral 
serpentine. He described also the mode of the change. The other 
minerals found in the serpentine rock are eustatitc, varieties of augite. 
