On the Action of Naphthalene on Plants. 1} 



By 



K. Aso. 



It has been shown by various authors that after treatment 

 of the soil with certain volatile substances, such as carbon 

 disulphide, ether or chloroform, plants developed more vigorous- 

 ly in such a soil. It seemed to me of some interest to observe 

 also the effect of less volatile substances as e. g. naphthalene. 

 This has the melting point = 79° C and boiling point = 218° and 

 volatilizes slowly at the ordinary temperature. 2) Since naph- 

 thalene has long been applied as a means to keep off moths 

 from clothing, and is also recently reported to drive off in- 

 testinal worms, an effect on nematodes in the soil might be 

 expected. Hollrung observed that insects may be kept off 

 from plants dusted with naphthalene, but he could not observe 

 any fungicide properties. A mixture of naphthalene and lime is 

 recently recommended to keep off earth fleas, larvae of Lema 

 asparagi and snails from young plants. 



An injurious effect on higher plants has thus far been not 

 reported. In contrary, W. Busse observed with barley grains, 

 that had been mixed for a certain time with 1% naphthalene, 

 a preservation of the germinating power for a longer time than 

 with the barley not thus treated. 



Before my experiments with phaenogams will be described, 

 some tests with bacteria and algae may be mentioned. 



To 100 c. c. of culture water 1% and 0.1^ naphthalene 

 respectively was added, and some filaments of Spirogyra nitida 



*) This article was published also in the Bulletin of the college of Agriculture, 

 Tokyo Imperial University. Vol. VIII, No. 3, 1907. 



2 ) I have observed in this regard the following: Ig. of naphthalene was left 

 covered with 100 cc. water in an Erlenmeyeb, flask plugged with cotton at 20°C. 

 After nearly one month the larger portion of naphthalene had sublimed into the upper 

 part of the flask. 



