CHAS. LENTZ & SONS 
embedains and freezing Apparatus. 
No. 2170. As Applied to Simple Microtome. 
Always ready. The most rapid and best freezer made. 
2170. Cafbonic Acid Freezing: Attachment, for the Microtome . . . $26 GO 
Refilling: Cylinder, with Carbonic Acid 475 
2172. PROFESSOR RYDER^S EMBEDDING APPARATUS 
This apparatus was made by us for the late John A. Ryder, of the University 
of Pennsylvania, and is intended for the embedding and cutting of exceedingly 
minute objects. 
It consists of a metal ring A, to which is attached by heated paraffin a sheet of 
filter-paper ^, the central circle being left absorbent. The whole is then placed 
upon a number of sheets of filter-paper. A thin section of elder pith C, is then cut 
and placed on top of this absorbent circle. The minute eggs, etc., having been 
placed on top of this disc of pith, a few drops of water are let fall from a pipette D. 
The filter-paper B thus absorbs all the water in the direction of the arrows and the 
small objects are thus entrapped and held fast in the meshes of pith. The disc is 
then removed with a pair of fine forceps, embedded in paraffin on its edge and 
sections cut with a sledge microtome. By this method Dr. Ryder has stained and 
obtained several sections of such small objects as Paramoecium aurelia also HaU 
teria (the latter are about the size of a white blood corpuscle). See " American 
Naturalist," February 7, 1895. Each, 50 cents. 
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