Schultze's Dehydrating ApparatusAuthor(s): Douglas H. CampbellSource: Botanical Gazette, Vol. 14, No. 7 (Jul., 1889), p. 183Published by: The University of Chicago PressStable URL: http://www.jstor.org/stable/2994689 .

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1889.] BOTANICAL, GAZETTE. 183

Scliultze's deliydratinig applaratus.-The accompanying figure shows a very convenient and simple arrangement for gradually dehydrating small objects. It consists of a wide-necked bottle (a), into whose neck is

fitted a short tube (b), and within this a

/( Vy^ \similar but smaller tube (c). In order to prevent these tubes from slipping down, the upper part is widened into a small fun- nel. Each of the tubes has the bottom closed by a piece of parchment paper,

/ _ _which is carefully gummed on. The object I

c . ^ to be dehydrated is placed in the tube c,

which is partly filled with weak alcohol (about 30 per cent.), and this is then placed in the tube b, which in turn is put into the

?2 - .. _ __ neck of the bottle a, which has been filled ~ ~-- - ~ with absolute alcohol. By the diffusion of

DEIHYDRATING APPARATUS, the fluid through the membranes covering the bottom of the tubes b and c, the density of the fluids will finally be- come the same, and the object in c will thus gradually be brought into practically absolute alcohol. The cover, d, effectually prevents evapora- tion and at the same time keeps out dust.

In order to prevent the alcohol in a from becoming too much di- luted, it is best to use a very small amount of the weak alcoh.ol, and a lit- tle calcined copper sulphate placed in the bottom of the bottle will absorb what little water may be present.

Usually two or three hours is sufficient for completely dehydrating most objects, but naturally large ones may take longer. Of course the process may be expedited by covering the bottom of only one of the tubes with the membrane, but it is usually better to have the diffusion take place rather slowly.--DOUGLAS H. CAMPBELL, Bloomington, Ind.

CURRENT LITERATURE.

On Nematopllyton and Allied Forms.1 Prof. Penhallow has presented in this short memoir a most valuable

contribution to our knowledge of one of the oldest and most perplexing forms that has claimed the attention of paleobotanists. The original ma- terial was collected by Sir W. E. Logan, from the Erian sandstones of Gaspe, about 1852. It was first examined by Dr. (now Sir) William Daw- son in 1855, who recognized at once the extreme interest attached to the

1PENHALLOW, D. P,-On Nematophyton and Allied Forms, from the Devonian of Gasp6, with introdluctory notes by Sir William Dawson. Tralls. Roy. Soc. Canada. Vol. VI. Sect. IV, 1888, pp. 27-47. P1. I, II.

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