Notes on scientific^research. 93 



valuable for the plant breeder since he can, by cross breeding of different varieties, 

 obtain novelties and improvements in any desired direction. 



In France the best species of lavender are under cultivation, and the oils obtained 

 from Lavandula vera fragrans and L. vera delphiniensis surpass all the products of other 

 lavender species growing in France, by their superior character 1 ). Both the varieties 

 thrive in the subalpine region at an elevation of more than 1300 feet in the south east 

 of the country. The Lavandula spica, D.C. which like the hybrid of Lavandula vera and 

 jsjpica gives a less good oil, mainly utilised in varnishes, grows at lesser altitudes. The 

 special properties of the English oil of lavender are likewise due to the long-continued 

 cultivation of the plant by a few breeders. 



Beautiful success has been obtained in Hungary with peppermint which has system- 

 atically been cultivated there since 1904 and has been improved by selective breeding. 

 One of the most successful early pioneers in this field was Father Joseph Agnelli, who 

 produced the "Agnelliana" varieties of Mentha crispa and Mentha piperita. 



The fact that Mentha species incline to hybrid formation may account for the manifold 

 variations of peppermint. One kind is known as red peppermint in France where it is 

 becoming more and more popular according to Smith; it grows on soil which would 

 be unsuitable for Mentha piperita, L. The red peppermint, moreover, may be grown for 

 -four or five years in succession on the same plot, whilst Mentha piperita, L. only thrives 

 two consecutive years on the same field. The yield of oil is greater with the former 

 species than with the latter; the product itself, however, is inferior. 



From the Deutsche Parfiimerie-Zeitung*) we take a few statements on the fight against 

 insect-pests, acquaintance with which may be valuable also for the cultivation of aromatic 

 plants. The Schweinfurt green (aceto-wefa-arsenite of copper), with which the Colorado 

 beetle was fought between 1860 and 70. in the United States of North America, is a 

 well-known general remedy against insect-pests. In Germany this poisonous preparation, 

 as well as Urania green and lead arsenite (Zabulone) were only used during the War 

 when the nicotine formerly applied disappeared almost completely from the market. 

 According to Stellwaag 3 ) the fight against insects by means of these arsenites is hygien- 

 ically free of objection, provided the spraying be stopped 5 weeks before the harvest. 

 On the other hand the Biologische Ueichsanstalt and the Reichsgesundheitsamt have pointed 

 out that grape-juice and wine may be poisoned when the vines are sprayed with arsenious 

 chemicals. A non-poisonous spray, recommended under the name of "resinol" by 

 the Chemical Works of F. Raschig, is the alkali or alkaline earth salt, soluble in water, 

 of an artificial phenolaldehyde resin. It has been applied with success by R. Falck 4 ) 

 against the caterpillar of the common white cabbage butterfly. Very good results have 

 been realised in this fight against insects by means of gases or volatile liquids like 

 sulphur dioxide, prussic acid and esters of the cyanocarbonic acid mixed with esters 

 of the chlorocarbonic acid (known in mixtures under the name of "Zyklone"). Whilst 

 we are not sure, when using substances suspended in water or dissolved in water, that 

 all the parts of the plant will be struck, the gases penetrate everywhere and destroy 

 all small life. On the other hand it is difficult to secure efficient action of the gases 

 in the open field. It is not stated how this difficulty is overcome. 



The animal pests of plants may, according to F. Zacher 5 ), be divided into two 

 groups:— 1. the oligophagi, which attack only a few species of plants related to one 



*) Cf. Gildemeister and Hoffmann, The Volatile Oils, 2 nd ed., vol. Ill, p. 421. — 2 ) Deutsche Parf. Ztg. 7 

 (1921), 16. — *) Zeitschr. f. angew. Entomologie 7 (1920), 172. — *) Ibidem 7 (1920), 37. — 8 ) Berichte d. 

 ieutsch. pharm. Ges. 31 (1921), 53; reprint was kindly sent to us. 



