i66 
THE ENERGY OF THE LIVING PROTOPLASM. 
to arouse the envy of the chemist and instigate him to try to 
accomplish the same ends. To these endeavours we owe a long 
series of interesting syntheses since the artificial preparation of 
urea by Wohler in the year 1828. Carbon and hydrogen were 
united in the electric arc by Berthelot; acetylene, thus formed, 
leads, among other things, to ethylene, ethyl alcohol, acetic acid, 
aldehyde, acetone, and glyoxal. Acetyle'ne yields at low red 
heat benzene, from which, again, numerous derivatives can be 
obtained. Acetone, further, may easily be converted into 
trimethyl-benzene, aldehyde into trimethyl-pyridine ; from pyri¬ 
dine, again, conine may be reached ( Ladenburg ). Glyoxal leads, 
by way of its cyanhydrin, to tartaric acid. 
Carbon can be united with aluminium and this product 
yields, by decomposition with water, methane (Moissan). Methane, 
again, yields methyl alcohol and formaldehyde, while the latter 
yields by condensation several kinds of sugars ( 0 . Loew). 
Formic acid can be obtained by the action of sodium upon moist 
carbon dioxide ( H. Kolbe), or by the action of iron filings upon 
bisulphide of carbon in presence of water in sealed tubes at 
ioo° ( 0 . Loew). Oxalic acid results by passing dry carbon 
dioxide over hot sodium amalgam ( E. Drechsel), or by treating 
the product of reduction of bisulphide of carbon by sodium 
amalgam with fusing potash or boiling baryta water ( 0 . Loew). 
From a mixture of oxalic ester and acetic ester aconitic acid can 
be obtained (L. Claisen and E. Hori) ; from acetone and oxalic 
ester, oxytoluic acid, and from this an anthracene derivative, 
(dimethyl-anthrarufin) was obtained (Claisen). From malonic 
ester phloroglucin can be reached (A. Baeyer), from succinic 
ester hydroquinone, from malic acid oxynicotinic acid and 
daphnetin (Pechmann). 
These and similar synthetic processes, are, however, for the 
most part only possible by the application of powerful agents, 
such as strong bases or acids, sodium alcoholate, sodium 
amalgam, chloride of zinc, etc., and partly by the aid of high 
temperature ; while no light is thrown upon the special method 
followed by the living protoplasm of plant-cells, a material consist¬ 
ing of proteids of neutral reaction or nearly so, and very easily 
changed by any substance with powerful affinities. The chemical 
agency consists here merely of specific waves. We are acquaint- 
