COMMERCIAL AND SCIENTIFIC NOTES ON ESSENTIAL OILS. 47 
- the acetylation value was thereby so increased, that an apparent menthol content 
of 89.3 per cent. resulted, i. e., an amount, which even in normal (unseparated) Japanese 
peppermint oil— which does not come into account here, — belongs to the exceptions. 
Two other samples, which were likewise offered as good cheap goods consisted 
wholly or at least partly of waste products, such as are obtained in the rectification 
of Japanese peppermint oil. The low quality shows itself especially in the low menthol 
content and the absolutely unsatisfactory solubility, not to mention the deviations in 
the constants and the change in odour. 
2): I, II. 
eye et re raat tS hes OO O0G: 0.8926 
Bee eee eg A034" ES 930.56! 
Solubility in 70 per cent. alcohol insoluble insoluble 
” — » 80 5 Mi IN ” Houde es further addition 
an a= GO : i sol. in 3 vols. — 
Saponification value . . . . . 7.0 er Lae by 
Ester value after acetylation . . 43.1 108.5 
Total menthol . . . . . .°. 124 percent. 32.9 per cent. 
Only last year we gave a few details over the occurrence and the combating of 
‘the peppermint rust, Puccinia Menthe, Pers. Since this dangerous rust disease has 
Z made itself noticeable for some time in various districts in which peppermint is 
cultivated the communications of G. Korfft) about this disease maybe of interest. 
; The peppermint rust attacks not only the cultivated Mentha species, but also wild- 
_ growing, and has been found on M. arvensis, M. aquatica, L. and M. viridis..L., as well 
as amongst the genera Calamintha, Melissa, Melittis, Nepeta and Satureja. According 
to the investigations of Cruchet2), with the rust fungi appearing on the Mentha species, 
_ it is a case of various forms of Puccinia Menthe suitable to the species in question, 
which forms only engender the rust discase on plants of similar kind. Since it is still 
uncertain whether the autoecic*) fungus as such winters inside the plant, or whether 
a new infection, caused by spores that have survived the winter, happens yearly, the 
spreading and overwintering of Puccinia Menthe should be everywhere carefully observed 
whenever there is an opportunity. Plants suffering from unfavourable conditions of 
_ growth are the most suitable victims of the peppermint rust. Hence in laying out a 
“peppermint plantation, it is well to see that all conditions favourable for a good 
development of the plants are fulfilled. In addition to.a suitable climate and good 
soil, the peppermint plant needs a suitable manure vich in potash. and phosphates, but 
not over-rich in nitrogenous fe ane : 
Oil of Perilla citriodora.— The labiata FPerilla citriodora, Makino®) discovered 
a few years ago near Tokio resembles much in appearance the P. ocymoides, L., but 
differs from the variety named, however, in the smell of lemongrass oil which -its 
_ leaves develop when rubbed. Kondo and S, Yamaguchi®) were able to obtain from 
_ the dried plant 2 to 3 per cent. of an essential oil of specific gravity 0.911 to 0.913. 
The oil contained 59.26 per cent. of citral. The oil remaining after separating the citral 
1) Heil- und Gewiirzpflanzen 2 (1918/1919), 205. — 7) Zentralbl. f. Bakteriol. u. Parasitenk. Abt. Il. 1906, 
212. — -%) The various spore forms appear on the one and the same plant which ‘nourishes them. — 
*) Cf. Reports October 1912, 91; 1917, 36. — 5) The plant has up to 1910 not been mentioned in the Index 
_ Kewensis. — *®) Pharm. Soc. Japan 446 (1919), 263. According to Journ. chem. Soc. 116 (1919), 492 and Parfum. 
moderne 12 (1919), 148. 
a 
