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1894.] Microscopy. 975 
MICROSCOPY.’ 
Cytological Methods.—Jysol_—Friedrich Reinke’ calls attention 
to the antiseptic lysol (a solution of Cresol in neutral soap) as a valu- 
able reagent for the nucleus. It dissolves chromatin, leaving other ele- 
ments intact; and it brings out a new element in the nucleus, to which 
the author gives the name, edematin. This substance appears in the 
form of granules within the linin mesh-work of the nucleus, remain- 
ing after the chromosomes have been completely dissolved. A small 
salamander larva, for example, left in about 50 cem. of 10 per cent /y- 
sol for from 6 to 24 hours, will have its chromatin dissolved, and its 
cedematin granules rendered visible. 
(Edematin shrinks greatly in such reagents as alcohol, chromic acid, 
and osmie acid, and only now and then appears as a fine granular pre- 
cipitate. In lysol, on the contrary, it swells up under the action of 
one constituent (the soap solution) and is coagulated by the cresol and 
thus made distinct.  CEdematin corresponds, in part at least, to 
Heidenhain's oxychromatin, Pfitzner's parachromatin, and Frank 
Sehwarz's paralinin. Reinke remarks that this substance is absent, or 
nearly so, from ova and spermatozoa. It is well developed in most 
somatic cells: e. g., epithelium, connective tissue, leucocytes, etc. 
In the action of lysol, three stages are to be distinguished : (1) solu- 
tion of the chromatin ; (2) appearance of edematin granules; and (3) 
further changes of the cedematin. 
The time required to reach the second stage varies with the tissue. 
The epithelium of the salamander larva requires at least six hours. In 
connective tissue the second stage is quite short and transitory. 
The method does not admit of permanent preparations. 
Neutral versus Acid Fixatives for Nuclei.'—Professor Alt- 
mann claims that the usual acid reagents, among which he reckons 
sublimate, platinum-chloride, gold-chloride, etc., disturb nuclear struc- 
ture, reducing the chromatic elements to compact, structureless masses. 
On the other hand, neutral reagents, among which are placed osmie 
acid, and a mixture of chromic acid with a molybdenum salt, preserve 
the structure of nuclei. At first sight, and under low powers, nuclei 
present a homogeneous appearance. But this homogeneity is not 
1Edited by C. O. Whitman, University of Chicago. 
^ Anat. Anz. VIII, Nos. 16 and 18, 1893, and Arch. f. m. Anat. XLIII, No. 3, 
1894. 
Altmann. Verhandl. d. Anat. Ges. Mag., 1893, p. 50. 
