1864. Microscopy. 685 
vibratile cilia, and contain siliceous spicules; some portions emit pro- 
cesses similar to those of Actinophrys, others become encysted. From 
the cysts from four to five monads emerge, provided with a single 
whip, and capable of swimming or performing amcebiform movements. 
Similar monads have been observed in the eggs of other low forms of 
invertebrates. 
Researches conducted with the aid of the microscope will doubt- 
less explain many strange phenomena, and place many facts within our 
comprehension which, before, were veiled in mystery. The discovery 
of fatty degeneration of the heart and liver has accounted for sudden 
deaths, which are of frequent occurrence, and where no diseased 
condition of body is perceptible to the unassisted eye. It appears, 
however, from the researches of M. Tigri, recently published in the 
‘Comptes Rendus, that this disease extends to the blood itself. A 
fatty substance has been found to accumulate in the red bloocd-cor- 
puscles which materially influences the circulation, and in the opinion 
of the author frequently produces death. 
Dr. T. F. Weisse, of St. Petersburg, gives a detailed account of 
the development of the eggs of Floscularia ornata, in the last. number 
of Kélliker’s ‘ Zeitschrift.’ Whilst the author was engaged in investi- 
gating the eggs of the Rotifera, he discovered a beautiful example of 
Floscularia ornata in his aquarium, which had already deposited four 
ova; a fifth was afterwards expelled from the animal under obser- 
vation by forcible contraction of the body. The germinal vesicle was 
still observable in this last ovum. No remarkable change took place 
in the ova for two days, until in one a bright red spot was observed, 
and on the following day two distinct eyes, which moved with the 
already-visible embryo ; other changes were observed in the course of 
the day ; ciliary motion appeared near one end of the embryo, and the 
pharynx exhibited movements at times. At the end of five days, the 
ovum was ruptured and the little animal issued from its shell, using a 
worm-like movement and showing clearly the circle of cilia at its 
anterior extremity. <A figure is given of the embryo at this period, 
when it bears not the least resemblance to the parent, and would easily 
be considered as a distinct species of animal. The development appears 
to take a considerably longer period than was generally supposed to 
obtain among the Rotifera. M. Weisse believes seven days to be the 
period passed by this species in the ovum after emission from the 
parent’s body. 
The application of photography to the delineaticn of objects be- 
neath the microscope does not advance in that rapid manner, or receive 
the amount of attention, which is to be desired. There can be no 
surer method of settling many disputed points of structural anatomy 
than the circulation of well-executed photographs of the objects under 
discussion. M. Duchenne, of Boulogne, has succeeded in obtaining 
some very accurate photographs of the microscopic appearances of the 
spinal chord of the human subject. The magnifying power used in 
obtaining these photographs was from 200 to 1,000 diameters. 
Dr. Clark, of Harvard University, has described the eggs ef Tubu- 
laria, in ‘ Silliman’s Journal,’ vol. xxxvii. His observations have led 
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