141 
THE MICROSCOPE. 
[Nature and Art, May 1, 1867. 
in the chignons, they could possibly germinate, I 
and thus pass from the artificial to the natural hair. 
This is all that can be fairly said in regard to the 
notorious “ gregarine ” discovery. 
The microscope has recently been employed with 
advantage in the study of physical geology. Sec- 
tions of fossils have frequently been examined under 
high magnifying powers, and many important points 
have been thus made out ; but till quite recently 
the microscope was not employed in the examina- 
tion of rocks. Mr. David Forbes, F.R.S., has 
called attention to the fact that rocks which it is 
difficult otherwise to distinguish from each other 
maybe readily discriminated when thin sections are 
placed in the field of the microscope. He himself 
has found this method of inquiry of the highest 
importance in the course of his numerous investi- 
gations into the metallurgical value of various 
minerals. Mr. Sorby, F.R.S., has also, we believe, 
employed the microscope to discern the intimate 
structure of metals and minerals, and is still en- 
gaged in researches of this kind. In the field of 
palaeontology (the science of fossils) the microscope 
has lately thrown much light on inquiries which 
could hardly have been completed without its 
assistance. Mr. Carruthers, of the British Museum, 
and Mr. E. Bay Lankester have made out some 
interesting points of structure by submitting thin 
slices of fossils to microscopic examination. The 
former has been engaged in examining our fossil 
plants, especially those from the coal formations, 
and has considerably modified what were before 
regarded as orthodox views. The latter has, 
with the assistance of the microscope, been able 
to show that a fossil fish examined by him is 
quite new to science. Of course, his conclusion 
is in some measure based upon the general form 
of the fossil, but the microscopic evidence is 
equally important. It so happens that in the 
family of fossil fishes known technically as the 
Ceplialaspidce there is one division the bones of 
which possess small irregular cavities with lines 
proceeding from them. These cavities are called 
lacunas, and in order to see them a very finely- 
ground thin slice of the bone must be placed under 
the microscope. In trying to discover the species 
to which his specimen belonged, Mr. Lankester 
submitted a delicate section to microscopic exami- 
nation, and he soon perceived that these lacunas were 
not only present, but were large, and “very densely 
packed, arranged at right angles in the different 
lamellce of the bony material, so as to produce the 
appearance of cross-hatching.” * This discovery 
removed much of the difficulty of the diagnosis, 
and helped, with the external characteristics, to 
indicate the true relations of the fish, which Mr. 
Lankester has named Didymaspis (cdovfioc, twin, 
and danic, shield). 
In the department of botany microscopists have 
not been idle. Herr Reichert has been exploring 
the circulation of the sap in plants, and has pointed 
out that of the two distinct portions of sap which 
* The Geological Magazine, April. 
are found in the little vesicles of which plants 
are built up, but one of them is engaged in rotation, 
the central fluid being always stationary. The phe- 
nomena of the circulation in plants may be seen by 
any of our readers possessed of a good microscope, 
by placing under a moderately high power a semi- 
faded leaf of that common canal weed, the Ana- 
charis alsinastrum. In France M. Chatin has been 
working at the anther, that little powdery seedlike 
body which is found at the top of the stamens of a 
flower. This was formerly considered to possess 
only two envelopes or linings ; but with the aid of 
the microscope M. Chatin has been able to distin- 
guish a third coat. In our own country the veteran 
Gulliver has been continuing his researches upon 
the microscopical structure of plants. Quite re- 
cently he has been examining the appearances of 
pollen-grains. The pollen is the fine soft powder 
which is discharged from the anther above men- 
tioned, and which one sees so abundantly distri- 
buted over the inner parts of the flower in the lily. 
Professor Gulliver has examined the pollen-grains 
of a large number of plants, and he has found not 
only that their particles have, when magnified, a 
definite shape and outline, but that these are gene- 
rally peculiar to each plant. This discovery is 
important, for it sIioavs that by means of the 
microscope Ave may often determine the exact 
species of a plant by a portion of its pollen sufficient 
to rest upon the head of a pin. 
In the study of the structure of the loAver 
animals, the employment of the microscope is in- 
dispensable. In this branch of anatomy a good 
deal has been recently achieved. Tavo neAv and 
curious species of wheel animalcule have been dis- 
covered by Mr. Henry Davis, and described by him 
to the Microscopical Society. Hitherto it Avas 
thought that only one wheel animalcule ( Melicerta ) 
had the power of constructing a habitation for 
itself Mr. Davis has shoAvn that this opinion is 
not correct, since he has seen the species he has 
discovered arranging the minute pellets one by one, 
and fastening them together by means of a glutinous 
substance into a veritable domicile. The little 
animalcule appears to be provided with a micro- 
scopically bearded chin, which is employed in the 
process of domestic architecture. The brain of 
that singular animal, the cuttle-fish, has been ex- 
amined under the microscope by Mr. Lockhart 
Clarke, and appears to be a Avonderful piece of 
nervous complexity. It has been always considered 
that the cuttle-fish is the highest of the animals 
devoid of an inner skeleton ; but Mr. Clarke’s 
researches, though of too special a character for 
further notice here, sIioav that the brain of the 
cuttle-fish is of a higher stamp of organization than 
was formerly supposed. 
Silk-worm culture is not simply an interesting 
pursuit for the dilettanti, it is a business of as much 
importance to the countries in Avhich it is folloAVed 
as any of the staple manufactures. Of late years, 
hoAvever, a sad blight has fallen on the French silk- 
Avorms, and has materially damaged the silk-trade. 
, To discover the cause of this was of the most vital 
