6 



BULLETIN 454, U. S. DEPARTMENT OF AGRICULTURE. 



Table IV .—Physical ■properties and chemical composition of peppermint oil distilled 

 from the fresh and from the dry herb at various stages of growth during successive years — 

 Continued. 





Physical properties. 





Chemical composition (per 

 cent). 



Year and descrip- 

 tion of material. 







Rota- 





Solubil- 



Free 



Ester 



Menthol. 





Color, odor, and taste. 



Specific 

 gravity. 



tion, 

 50 mm. 



Refrac- 

 tion. 



80 per 



cent 



alcohol. 



acid 

 (as 



thyl 

















tube. 





acetic). 



tate). 



Free. 



Total 



1909. 





















Dry herb: 







° 





Volumes. 











Budding 



Greenish yellow; 

 strong minty odor; 

 pungent, minty 

 taste. 



o0. 9337 



-13.1 



61. 4695 



c 1.2 



0.17 



13. 26 



36.07 



46.38 



Flowering 



Golden yellow; 

 minty odor; pun- 

 gent, minty, slight- 

 ly fatty taste. 



a. 9163 



-13.5 



61. 4695 



(d) 



.16 



12.73 



37.37 



47.44 



Fruiting 



Yellow; unpleasant 

 minty odor; strong, 

 pungent, minty 

 taste. 



a. 9344 



- 8.1 



''1.4718 



el 



.36 



17.68 



34.2 



48.15 



1910. 





















Fresh herb: 





















Budding 



Dark golden; not 

 fragrant, minty 

 odor; slightly bit- 

 ter,pungent, minty 

 taste. 



/. 9155 



-12.1 



nl.4718 



g.7 



.86 



16.62 



43.76 



56.85 



Flowering 



Pale yellow; mild, 

 agreeable odor; fat- 

 ty, strong, cooling, 

 pungent taste. 



Z.9273 



-5.7 



al. 4820 



e.6 



.03 



11.67 



30.94 



40.13 



Fruiting 



Yellowish green; 

 very fragrant flow- 

 ery odor; very bit- 

 ter and slightly 

 pungent taste. 



/.9250 



— 7 



ol.4712 



ft. 8 



1.14 



20.86 



12.7 



29.14 



Dry herb: 





















Budding 



Light golden; herb- 

 like, faint, minty 

 odor; slightly bit- 

 ter, pungent,minty 

 taste. 



/.9167 



-11 



al. 4724 



h. 6 



1.20 



19.80 



39.41 



55.01 



Flowering 









ol. 4765 





3.20 



30.41 







like odor; pungent 





















and cooling taste. 



















Fruiting 



Golden yellow; fra- 

 grant, pleasant 



/. 93S3 



— 3.3 



«1. 4713 





.56 



20.51 

























odor; very bitter 





















and slightly pun- 





















gent taste. 



















1911. 





















Fresh herb: 

































.06 

 .20 



12.02 



13.79 



32.37 

 34.11 



41.84 















44.97 

















a At 22° C. 

 6 At 25° C. 

 « Turbid in excess. 



d Turbid iu 1 volume absolute alcohol; insoluble 

 in 80 and 90 per cent alcohol in any proportion. 



e Turbid in 2 volumes or more. 

 /At 24° C. 



g Turbid in 4 volumes or more. 

 h Turbid in li volumes or more. 

 * Turbid in if volumes or more. 



Table IV shows that the oils distilled from the fresh herb collected 

 at the three stages of growth show only slight differences hi their 

 general properties — color, odor, and taste. The oils from the flower- 

 ing plants show a higher specific gravity and comparatively lower 

 rotation than those from the budding and fruiting stages. With 

 respect to their solubility in 80 per cent alcohol the several oils vary 

 considerably. 



