720 The American Naturalist. [August, 
following compounds caused repulsion: organic and inorganic acids, 
alkalies, alcohol, calcium nitrate, magnesium sulfate, sodium chloride, 
potassium nitrate, chlorate and chloride. The nutrient value of a sub- 
stance, it is said, in no way corresponds to its chemotropic stimulus. 
Glycerin is cited as example of a good food which has scarcely any 
chemotropic action. The five molds were specially attracted by sugar, 
while the Botrytis showed a special preference for meat extract and 
peptone and no liking for grape or cane sugar. The pollen tubes were 
indifferent to meat extract, peptone and asparagin, but were attracted 
by grape sugar, cane sugar, dextrin and plum decoction. The title of 
this paper is Ueber Chemotropismus der Pilze. It oceupies all of Botan- 
ische Zeitung. 52 Jahrg. 1 Abt. Heft I., and is well worth reading by 
all who are interested in the cultivation of fungi. 
—Erwin F. SMITH. 
ZOOLOGY. 
Origin of Life.—The following interesting speculation as to the 
origin of the organic forms of the earth is advanced by Mr. Charles 
Morris. There was a time in the earth’s history, when chemical inac- 
tion prevailed, on account of high temperature and unfavorable phys- 
ical conditions, but, on the formation of an ocean of highly heated 
waters, holding in solution a variety of elementary substances and simple 
compounds, chemism grew active, and became more energetic as the 
waters increased in depth and in variety and volume of their contents. 
Many complex minerals were very likely then formed and deposited as 
rock formations. As the ocean became freed from its abundance of 
foreign material inorganic chemistry decreased, until now it has prac- 
tically ceased, oxidation having reduced nearly all substances to a state 
of chemical fixity. 
As the waters of the primeval ocean slowly cooled, and inorganic 
chemism declined in activity, organic chemism probably set in, aided 
by the solar rays. The material for this new phase of action had been 
prepared and existed abundantly in the water and air. It may have 
had its origin in an early reaction between carbon dioxide and the 
elements of water, yielding the hydro-carbons ; and subsequently be- 
tween these and nitrogen, yielding the far more complex albuminous 
compounds. 
