228  Miscellanies. 
dilute nitro-muriatic acid. One would have thought that, after such 
treatment, the quartz could have contained nothing capable of sustain- 
ing vegetable life; nevertheless the plants grew in it, and their ashes 
were found to contain potassa, lime, magnesia, and silicious earth, 
which had been obtained from the decomposition of the quartz sand by 
the decomposition of the roots.”,—Gardener’s Chronicle. (We see no 
proof nor probability that the carbonic acid in such cases is disengaged 
from the roots.) 
7. Filarie in the Blood of a living Dog.—MM. Gruly and Dela- 
fond exhibited to the Academy of Sciences, at their session, Feb. 6th, 
numerous specimens of an Entozoon, allied to the Filarie, obtained 
from the blood of an apparently healthy dog. Physiologists have been 
for a long time aware of the presence of Entozoa in the blood of rep- 
tiles and fishes, but this is the first instance in which they have been 
detected in the blood of a mammal. It is of great importance to physi- 
ology, pathology, and natural history, to prove not only their existence 
in the blood itself, but that they circulate with it in the higher animals. 
The entozoa in question, have a length of 0.25 millimetre, and a di- 
ameter of 0.003 to 0.005 millimetre. Body transparent, colorless ; 
anterior extremity obtuse, posterior terminated by a thin filament. 
Their motions are very active, swimming with an undulating move- 
ment among the globules. ‘They were detected in the blood drawn 
from the coccygeal arteries, external jugular veins, capillaries of the 
conjunctiva, mucous membrane of the mouth, skin and muscles. The 
urine and excrements contained none. ‘Their diameter is less than that 
of a blood globule, which will allow them to pass wherever the blood 
circulates.— Comptes Rendus, Feb. 6th, 18438. 
8. Experiments of Karsten, relative to the formation of the “* images 
of Moser ;” extracted from letters of Humboldt to Arago.—* On pla- 
cing a medal ona glass plate, and under the last a metallic plate, Kars- 
ten has ascertained that an image of the medal is formed upon the up- 
per surface of glass, when an electrical spark is made to fall on the 
medal. If the medal rests on several plates of glass, and the last on 
metal, the spark produces images on all the plates, but only on their 
upper surfaces ; the most feeble being the most distant from the medal. 
To render the images visible, they must be exposed to the vapor of 
iodine or mercury. The spark is necessary for the production of 
images. M. Karsten has not succeeded with the electricity of the 
pile.” (Berlin, 10th March.) 
‘“‘] have seen experiments of M. Karsten; the effect is instantaneous, 
and the figures very distinct. The electricity emanating with greater 
