BIOLOGY. 261 



water through the blood-vessels and the excretory canals, aud 

 then washes the water out by a current of alcohol. 



2. For destroying the fat he follows the alcohol with ether, 

 which he pushes through the same blood-vessels aud excretory 

 ducts. This part of the operation lasts some hours. The ether 

 penetrates the interstices of the flesh, and dissolves all the fat. 

 The piece, at this point of the process, may be preserved any 

 length of time desired, plunged in ether, before proceeding to the 

 final operations. 



3. For the tanning process he dissolves tannin in boiling dis- 

 tilled water, and then, after washing the ether out of the vessels 

 with distilled water, he throws this solution in. 



4. For the drying process he places the piece in a vase with a 

 double bottom filled with boiling water, and fills the places of thu 

 preceding liquors with warm, dry air. By the aid of a reservoir, 

 in which air is compressed to about 2 atmospheres, and whidi 

 communicates, by a stopcock and a system of tubes, first to a 

 vase containing chloride of calcium, then with another heated, 

 then with the vessels and excretory ducts of the anatomical piece 

 in course of .preparation, he establishes a gaseous current which 

 expels in a very little time all the fluids. The operation is now 

 finished. 



The piece remains supple, light, preserves its size, its normal 

 relations, its solid elements, for there are no longer any fluids in 

 it. It maybe handled without fear, and will last indefinitely. The 

 discovery is important, and will enable the medical schools to 

 provide themselves with full cabinets of natural and pathological 

 specimens. 



MUTABILITY OF SPECIES. 



In a recent communication to the Geological Society of Paris, 

 M. A. Gaudry pointed to some striking facts favorable to the 

 theory of the mutability of species. The sand pits in the environs 

 of Paris, and indeed all drift deposits in general, are very rich in 

 remains of -the mammoth or primitive elephant, and of the elephas 

 antiquus. These remains chiefly consist of molar or back teeth, in 

 which characteristic differences may be easily recognized. They 

 consequently pertain to two different species, and, in order to 

 ascertain whether there exists any close parentage between them, 

 M. Gaudry goes back to the pleistocene period, which lies be- 

 tween the upper tertiary or pliocene and the drift strata. Now 

 the pleistocene forest-bed of Norfolk contains a quantity of molars 

 of each of the above species, but it also comprises others slightly 

 differing from both, and also intermediate between those of elephas 

 aniiquus and elephas meridionalis, the latter ceasing to exist when 

 the former and the mammoth begin. These again disappear 

 after the drift, and are followed by other species. Here, then, we 

 perceive a succession of species, each of which has sprung from 

 the preceding one. During the tertiary period there existed a 

 breed of horses to which paleontologists have given the name of 

 hipparion. They had small, lateral finders, thus forming a link 



