OLDENBUSCH: STIMULATION OF PLANTS 387 
Complete inhibition was not found in any of the experiments 
tried, although the flasks containing M/5,000 solution only pro- 
duced felts of approximately three-fourths of the normal weight. 
In some instances the M/10,000 acted slightly as an inhibitor so 
that growth below normal was produced. 
SUMMARY 
All things considered, the results of this investigation lead 
one to conclude that carbon disulphide acts on plants as many 
other chemical stimulants do. When applied either in aqueous 
solution or in vaporized condition it inhibits growth, if given in 
too concentrated a solution or if vapor is used for too long a time. 
When used in dilute amounts, carbon disulphide has the 
ability to stimulate: 
(1) Dormant protoplasm, as in the case where twigs exposed 
to CS, vapor for a short period of time quickly resumed their 
growth; : 
(2) Active protoplasm, as in case where the hypocotyls of 
Vicia seedlings elongated more antes upon the addition of 
small amounts of CS,; 
(3) Conidial spores of certain fungi which germinated sooner 
and produced germination tubes elongating more rapidly, the 
stimulation causing also causes an increase in dry weight. 
Carbon disulphide acts also as other stimulants do, in that the 
acceleration of growth lasts only for a certain period of time, 
and then growth tends to reach normal again. This fact was 
shown in the twig experiments and those with Triticum grains. 
The same would probably be true of the other experiments if 
left running for a sufficient length of time. 
BoTANICAL DEPARTMENT, 
BARNARD COLLEGE 
COLUMBIA UNIVERSITY, 
New York City 
LITERATURE CITED 
1. Raulin, J. Etudes chimiques sur la végétation. Ann. Sc. 
Nat. Bot. V. 12: 91-156. 1869. 
2. Pfeffer, W. Ueber Election organischer Nahrstoffe. Jahrb. 
Wiss. Bot. 28: 205-268. 1895. 
