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MICROSCOPY. 569 
medullated fibres. He claimed priority of discovery in many 
cases, where it had been awarded by Dr. Klein to the German his- 
tologists. Many details of structure were given in his elaborate 
rawings, which are not explained at length in the text, for English 
readers will not read long and minute descriptions of such things. 
CRYSTALLINE Forms IN Grass.— The beautiful fern-like clusters 
of acicular crystals which are liable to form in a vitreous mass 
slowly cooling, have been described by the t Monthly Microscop- 
ical Journal ” and by “ Science Gossip ” as produced artificially in 
blowpipe beads and in porphyrine, and as occurring naturally in 
pitchstone. Such a crystallization often takes place as an accident 
in a mass of slowly cooling glass, as when, at glass works, the 
melted contents of a retort become accidentally ruined and they are 
allowed to cool and be thrown away. ‘The crystals produced under 
such circumstances are generally confused and merely form opaque 
masses or layers in the brilliant glass; but sometimes, as in a 
beautiful mass kindly furnished to the writer by Mr. Harding of 
the glass works at Berkshire, Mass., the crystalline clusters form 
distinct stars or rosettes imbedded in perfectly clear glass and 
looking wonderfully like what almost every microscopist has 
Wished he could make — snow-flakes perfectly and permanently 
preserved. The beauty of these objects is realized only when they 
are examined on a black field and by the binocular, and preferably 
by reflected light. 
Tur Levucocyrrs.— Dr. J. G. Richardson’s report to the Amer- 
ican Medical Association, “ On the Structure of the White Blood 
muscles,” was essentially a reassertion of the previously pub- 
lished doctrine of the identity of the white corpuscles of blood, 
-Pus and saliva. He is satisfied that they all act essentially alike 
in saline solutions, and that the salivary corpuscles are not only 
like white blood corpuscles distended by endosmosis when immersed _ 
i a fluid less dense than serum, but that they may, when acted upon 
by a dense saline solution, contract to the size of the white blood 
corpuscle and exhibit like amæboid movements. He also strongly 
isists upon the presence of a cell-wall, a question which loses 
much of its definiteness as well as its importance in view of the 
fact that the discussions of Dr. Beale have led many if not most 
investigators to the belief that the cell-wall, in general, is only an 
accident of age and circumstance, rather than an indispensable and 
