Am.  Jour.  Pharm. 
May,  1903. 
Commercial  Aloes. 
207 
vitreous,  have  a  conchoidal  fracture,  dark  brown  color,  peculiar 
odor  and  bitter  taste.  It  should  give  transparent  splinters  that  do 
not  show  crystals  under  the  microscope." 
In  addition  to  these  physical  properties  the  same  Pharmacopoeia 
also  gives  a  number  of  tests  for  identity  and  purity,  some  of  which 
will  be  referred  to  in  connection  with  the  discussion  on  the  chemical 
constituents  of  aloes. 
While  it  is  true  that  the  German  Pharmacopoeia  does  not  specifi- 
cally call  for  Cape  aloes,  or  aloes  from  Cape  Colony,  Schneider  and 
Siiss,25  in  their  commentary,  say  that  Cape  aloes  is  the  only  avail- 
able variety  that  corresponds  in  all  respects  to  the  requirements  of 
this  Pharmacopoeia. 
This  restriction  to  Cape  aloes  has  been  extensively  commented 
upon,  but  usually  favorably.  Of  the  arguments  that  have  been 
advanced  in  favor  of  this  variety  of  aloes,  we  may  mention  that 
in  1  Germany  this  grade  of  aloes  is  usually  considered  the  most 
reliable  as  well  as  the  most  active.20  Then,  too,  the  argument  has 
been  advanced  by  drug  brokers26  that  Cape  aloes  is  always  available 
and  usually  in  sufficient  quantities  of  uniform  quality.  In  the  past 
forty  years  it  is  said  Cape  aloes  has  been  scarce  but  once,  while 
other  varieties  have  been  repeatedly  scarce  and  sometimes  disap- 
peared entirely. 
Despite  the  fact  that  Cape  aloes  has  been  an  article  of  commerce 
for  upwards  of  125  years,  the  botanical  source  of  the  drug,  as  well 
as  the  exact  method  of  gathering  and  preparing,  has  been  the  subject 
of  much  controversy. 
Professor  Tschirch,  in  a  recent  number  of  the  Schzveizerische  Woch- 
enschrift}*  states  that  Cape  aloes  is  obtained  exclusively  from  Aloe 
Ferox,  Miller. 
The  gathering  of  the  juice,  it  appears  from  the  same  article,  is 
still  carried  on  in  the  old  primitive  method,  very  much  the  same  as 
that  followed  on  the  Island  of  Socotra ;  a  depression  in  the  ground 
is  lined  with  a  goat-  or  sheep-skin  and  the  butt  ends  of  the  aloe 
leaves  are  placed  so  that  the  exuding  juice  will  flow  into  the  recep- 
tacle so  formed.  After  draining  for  several  hours,  the  heaps  of 
leaves  are  scattered  and  the  wilted,  partially  dried  ends  cut  off; 
then  the  leaves  are  again  placed  to  drain  into  the  receptacle  formed 
by  the  skin-lined  depression  ;  when  this  is  filled,  or  when,  after 
repeated  clippings,  the  leaves  are  quite  exhausted,  the  exuded  juice 
