INFLUENCE OF CAEBON BISULPHIDE ON FEETILITY. 57 



to kill all the insects in that layer of earth. But solvations and emul- 

 sions of CSo do not act so rapidly nor so energetically as the vapour 

 in a closed space. A 1 per cent solution does not kill the phylloxera 

 until after twenty-four hours' immersion. Grubs strongly resist it. 

 Those of the gypsy moth, Ocneria dispar, L., resist soapy emulsions 

 containing up to 10 per cent CSg. Burleso Dufour came to the same 

 conclusions after trying to kill the cochylis (Conchylis ambig?iella, 

 Hubn) by emulsions containing 3 per cent and 10 per cent of CS2. 



Action of CS.j on Fungi. — This insecticide only acts on fungi in 

 very strong doses, and is only used to kill root rot. 



Influence of CSo on Fertility of Soil. — Carbon bisulphide, far 

 from injuring the soil into which it is injected, as believed at the out- 

 set of its use in vineyards invaded by the phylloxera, exerts even in 

 strong doses a favourable influence thereon. Aime Girard was the 

 first to observe that carbon disulphide injected into the soil produced 

 salutary effects on the soil treated, and greatly improved exhausted 

 soils. In Alsace-Lorraine, where the antiphylloxeric treatment to 

 extinction has so long been used, the marvellous action of carbon 

 disulphide has been remarked by Uberlin. The latter, who has more 

 especially studied the soil cure, has obtained surprising results. The 

 culture of the vine being rigorously forbidden during the next ten 

 years after the extinction treatment, the land was utilized for other 

 crops. Now it was found that in all these soils all species of plants 

 developed in a surprising manner, and that the rotations in use on 

 non-disinfected ground were unnecessary on the former ; CSo re- 

 generates exhausted soils and allows continuous growing of the same 

 crop. All papilionaceae may be profitably cultivated on lucerne 

 ground ; for example, if the soil of the latter is previously tilled and 

 disinfected, whilst in ordinary cropping one plant cannot usually be 

 grown after another of the same nature without intermediate crops ; 

 CSo therefore renders rotations unnecessary, and enables the same 

 plant to be cultivated for several years in succession. Oberlin, who 

 has greatly helped to popularize carbon disulphide, got, like Girard, a 

 double crop of trefoil after disinfecting the soil, and an appreciably 

 increased yield with grain crops, beets, potatoes, and farm crops 

 generally. In a tares (Vicia villosa) experimental field, treated with 

 CSo, Oberlin obtained, in 1893, 45 tons of green fodder per hectare 

 (18 tons per acre), whilst in a non-disinfected field, used as a test, the 

 yield was only 19 tons per hectare (7-6 tons per acre). He also ex- 

 perimented with haricots, and obtained by weight per are 85 kilo- 

 grammes in non-treated ground, and 125 kilogrammes in treated 

 ground. Oberlin disinfects the soil as follows : Holes about 12 

 mches deep are excavated by an iron bar and 25 grammes of CSg 

 run into each hole and the holes quickly closed ; 10 kilogi-ammes of 

 carbon disulphide must be buried per are. Three weeks after this 

 treatment sow the seeds. Practical experiments on vines gave equally 

 good results. Oberlin first, then Dufour, found that vineyards, before 

 being replanted, have no need, as generally believed, of a rest, nor of 

 any improvement by an intermediate crop after treatment with CSg. 

 The new vine can, in fact, be replanted as soon as the old stocks have 



