VOLUME LXII NUMBER 5 
te eS 
DOTANICAL  O4AZEITE 
NOVEMBER 1916 
CHEMOTROPISM IN RHIZOPUS NIGRICANS* 
ARTHUR HARMOUNT GRAVES 
(WITH FOUR FIGURES) 
Historical 
In view of the important relation of the question of chemotro- 
pism among the fungi to the problems of fungal parasitism, it is 
surprising that investigations in this field have been so meager; 
for while numerous scattered observations may be found here and 
there in the literature, the works of Mrvosni (8) and Futon (5) 
Stand out as the only ones which represent any considerable 
investigations of the subject. The researches of CrarK (3), 
although intended primarily to supplement his work on the toxicity 
of copper compounds, are also of especial importance in this 
connection. 
It is needless to enter here into a detailed historical account of 
all the researches from which information can be culled regarding 
chemotropism in the fungi, for an excellent review of these may be 
found in FuLron’s paper. It is our purpose merely to outline 
the results obtained by Mrvosut, CLARK, and FuLton. 
Mrvosut (8) tested a great variety of chemical substances, and 
maintained that in many cases they exerted a very marked attrac- 
tion on the fungal hyphae, which then grew toward them (positive 
chemotropism); others showed a repellent effect, so that the 
hyphae grew diametrically away from the diffusion center (negative 
* From the Department of Plant Physiology and Pathology, Imperial College of 
Science and Technology, London. 
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