THE MIcROscoPE. 165 
were transmissible to posterity. Weismann, on the other hand, 
regards acclimatization rather as the product of selection, such 
individuals surviving who, by the possession of inherent quali- 
ties, are enabled to live under the changed conditions, and not 
that they acquire new powers. Much, however, turns upon 
what is meant by an acquired quality. Weismann means by it 
such as is imparted by some external agency, and would limit 
the influence of external causes to unicellular organisms, where- 
as variation occurs through sexual reproduction. But, as Vir- 
chow points out, external agencies ought not to be limited to 
those which operate outside the organism. In a multicellular 
organism variation may occur in some cells, through the opera- 
tion of other cells—i. e., strictly within the body. Indeed, the 
influence of the sperm-cell upon the germ-cell is an external 
influence, and, therefore, although we speak of inherited quali- 
ties as being internal or predisposing, in strictness the qualities 
transmitted from the male parent are the result of an external 
agency when contrasted with those derived from the germ-cell. 
Applying these considerations to pathological processes, he 
shows that these are the result of external agents, and that 
they produce a change in the typical organization, and thus by 
mere analogy the conclusion is arrived at that many racial—nay, 
even specific and generic—differences have been brought about 
by processes which may be deemed pathological. The various 
factors which determine the persistence of such deviations, and 
their transmission by inheritance, are not fully known; use and 
disuse explain some, adaptation accounts for others; but, how- 
ever explained, the fact that acquired qualities are inheritable 
remains assured.— Lancet. 
SEPARATING THE LAYERS OF THE Wines or INsEcTS.—A wing 
that has never been dried is placed in 70 per cent. alcohol, then 
into absolute alcohol, and after a few days immersion then 
placed into turpentine. After remaining a day or two in the 
turpentine, the specimen is plunged suddenly in hot water, 
when the conversion of the turpentine into vapor between the 
two layers of the wing so far separates these layers that they 
can be easily parted and mounted in the usual way, as micros- 
copical preparations on a slide.-— Royal Microscopical Journal: 
