AmMay!"Sarm'}     Oil  of  Sandalwood,  Lavender  and  Thyme.  223 
PHYSICAL  AND  CHEMICAL  EXAMINATIONS  OF  OIL  OF 
SANDALWOOD,  LAVENDER  AND  THYME. 
By  Lyman  F.  Kkbi.br. 
The  quality  of  an  essential  oil  is  influenced  in  many  ways,  the 
locality  in  which  the  plant  is  grown,  nature  of  the  soil,  humidity  of 
the  air,  drought,  elevation,  cultivation,  methods  of  distillation,  etc. 
For  example,  lavender  oil  prepared  from  flowers  grown  in  the  lower 
mountainous  regions  of  the  Alps  is  inferior  to  that  distilled  from 
flowers  collected  at  an  elevation  of  5,000  feet,  and  the  oil  obtained 
from  flowers  cultivated  in  England  is  of  a  much  different  quality 
than  that  made  from  the  wild  alpine  flowers.  Prolonged  distillation 
undoubtedly  has  a  marked  influence  ;  oxidizing  some  products  and 
decomposing  others.  Mr.  H.  Laval,1  in  a  very  interesting  and  in- 
structive paper  on  lavender  oil,  deals,  in  part,  with  the  various 
distillation  methods  employed,  and  according  to  his  observations  it 
would  not  be  surprising  to  meet  with  as  many  qualities  of  oil,  from 
the  same  locality,  as  there  are  methods  of  distillation  employed. 
In  order  to  differentiate  between  good  and  poor  oils,  the  nasal 
organ  as  well  as  physical  and  chemical  methods  are  resorted  to. 
A  well  trained  and  experienced  nose  is  probably  very  difficult  to 
dispense  with  in  selecting  oils  for  certain  kinds  of  preparations. 
We  are,  however,  coming  more  and  more  to  determine  the  value  of 
an  oil  by  the  amount  of  the  most  essential  constituent  contained  in 
it.  Just  as  the  per  cent,  of  morphine  determines  the  value  of  opium, 
or  quinine  that  of  calisaya  bark,  or  strychnine  nux  vomica,  so  the 
amount  of  cinnamic  aldehyde  determines  the  value  of  oil  of  cassia, 
and  linalyl  acetate  and  santalol  are  valuable  factors  in  determining 
the  quality  of  oils  of  lavender  and  sandalwood,  respectively.  But 
even  here  we  have  conflicting  opinions;  for  example,  one  source  of 
information  tells  us  that  the  higher  the  per  cent,  of  ester  the  better 
is  the  oil,  from  another  source  we  learn  that  an  extended  investiga- 
tion shows  that  an  oil  containing  from  25  to  30  per  cent,  of  ester  is 
superior  to  an  oil  containing  from  35  to  40  percent,  or  over.  There 
are  certainly  good  reasons  for  such  differing  views.  The  high  test- 
ing ester  oil  may  have  had  its  aroma  injured  in  some  way  as  by 
distillation  or  careless  keeping,  or  certain  esters  may  have  been 
added  to  an  inferior  oil  to  bring  up  the  per  cent,  of  ester.  Again, 
1  1886,  J.  de  Pharm.  et  de  Chim.,  5,  13,  593. 
