EFFECT OF SOIL AND CLIMATE ON THE COMPOSITION OF PEPPERMINT 
OIL. 
Henderson states 1 that peppermint plants grown on a river bank 
on heavy loam and on deep sandy loam yielded oils which showed 
distinct differences in composition. According to Umney, 2 soil and 
climatic conditions are responsible for the higher content of esters in 
some peppermint oils than in others. Charabot and Hebert 3 have 
shown that the formation of certain constituents of the oil, and 
especially the esters, is favored by treating the soil with sodium chlo- 
rid and sodium nitrate. Mossier 4 has also observed that certain fer- 
tilizers, such as saltpeter, superphosphate, and potash, tend to favor 
the growth of the plant and the production of oil therein. 
In order to study the effect of various types of soil and climatic 
conditions upon the general composition of peppermint* oil, plants 
were grown at Webster, S. Dak., on rich black loam soil; at Glenn 
Dale, Md., on light sandy soil; and at Arlington Farm, Va., on heavy 
clay soil. The yields of oil distilled from these plants and also the 
physical and chemical properties were determined, and the results are 
given in Table I. 
Only very slight differences are noted in the yield of oils obtained 
from the plants grown on the different soils. The physical proper- 
ties — color, odor, and taste — likewise show only slight variations. 
The specific gravity of the Arlington oils distilled during two seasons 
are lower than the South Dakota or Maryland oils. The rotation 
and refraction of the various oils differ considerably. The Arlington 
oils are slightly more soluble in 80 per cent alcohol than either of the 
other oils. 
Comparing the chemical composition of oil distilled from the 
plants grown at Arlington with that from the South Dakota plants, 
it will be seen that the latter is richer in both esters and total menthol, 
while the ester content of the oil from Maryland plants is much 
greater than in either of the other oils. 
From these results and from results obtained by other observers it 
may be inferred that light soils of either a sandy or loamy nature are 
more conducive to the production of esters and menthol in the oil 
than soils of heavy texture. In the case of the oils first compared it 
is probable that the climatic conditions during the growing period 
acted jointly with the soil conditions to bring about the difference in 
the oils. This relation, however, did not apply to the oils produced 
1 Henderson, H. J. An experiment in peppermint culture. In Pharm. Jour., v. 87 (n. s., v. 33), no. 2493, 
p. 175-176. 1911. 
2 Umney, J. C. The effects of climate and soils on oils of peppermint. In Pharm. Jour., v. 57 (s. 4, v. 
3), no. 1362, p. 103-104. 1896. 
3 Charabot, Eugene, and Hubert, Alex. Influence de la nature de milieu exterieur sur l'&at d'hydra- 
tation de la plante. In Compt. Rend. Acad. Sci. [Paris], t. 136, no. 3, p. 160-163. 1903. 
< Mossier, Gustave. Ueber den Einfluss verschiedener Kulturbedingungen auf das atherische Oel von 
Mentha piperita. In Pharm. Post, Jahrg. !3, no. 1, p. 2-5. 1912. 
