190 
EDITOIAL. — PEREIRA's  MATERIA  MED1CA. 
No  chemical  formula  has  been  given  for  aconitina,  although  this  alkaloid 
has  been  investigated  recently  by  Von  Planta.   (Chem.  Gaz.  vol.  viii.  352.) 
The  additions  to  the  animal  substances  relate  to  wax,  isinglass, 
cochineal,  cod-liver  oil,  spermaceti,  castoreum,  and  hyraceum. 
The  following  note  on  the  manufacture  of  carmine  is  taken  from  the 
papers  of  the  author. 
"Carmine  is  prepared  from  blade  cochineal.  A  decoction  of  the  insect 
in  water  is  made.  The  residue  is  called  carmine  grounds,  (used  by  the 
paper  stainers.)  To  the  decoction  is  added  a  precipitant,  say  bi-chloride  of 
tin.  Alum  will  not  answer,  as  the  color  is  very  different.  The  decoction 
to  which  .bi-chloride  has  been  added  is  put  into  wash  hand-basins  and 
allowed  to  stand.  Slowly,  a  deposit  takes  place.  It  adheres  to  the  side  of 
the  vessel,  and  the  liquid  being  poured  off,  it  is  dried.  Artificial  heat  can- 
not be  used,  as  it  changes  the  color  of  the  deposit  j  neither  can  solar  light  be 
employed  for  the  same  reason.  This  precipitate,  when  dried,  is  carmine, 
[the  liquor  is  called  liquid  rouge.]  It  can  only  be  made  in  certain  states, 
of  the  weather.  If  the  weather  be  too  hot,  the  liquid  soon  becomes  sour, 
and  the  deposit  is  re-dissolved;  flies  also  injure  it.  If  carmine  be  not  dry 
it  is  apt  to  become  mouldy. 
"The  decoction  from  which  carmine  has  been  precipitated  yields  a  fur- 
ther precipitate  on  the  addition  of  more  of  the  precipitant;  but  the  product 
thus  obtained  is  darker  colored,  and  is  sold  to  the  color  makers  as  "lake." 
The  new  views  of  Mr.  Brodie  on  the  constitution  of  wax  are  noticed,  but 
the  more  recent  observations  on  Chinese  insect  wax,  by  Mr.  Hanbury,  are 
not ;  probably  because  they  were  published  too  late.  The  article  on  isin- 
glass has  been  enlarged  by  several  extracts  from  the  author's  papers  pub- 
lished in  the  Pharm.  Journal ;  the  editors  have  given  some  remarks  on 
Swineburn's  refined  isinglass:  and  on  the  testing  of  gelatin,  which  are  con- 
cluded by  the  following  paragraph. 
"  Much  absurd  discussion  has  arrisen  as  to  whether  gelatin  is  to  be 
regarded  as  a  product  or  an  educt  of  the  tissues.  It  is  an  educt  of  the  swing- 
ing bladder  of  the  sturgeon,  and  is  properly  regarded  by  the  author  as  a  con- 
stituent forming  from  86  to  93  per  cent,  of  isinglass.  If  an  educt  of  the  air 
bladder  of  the  sturgeon,  it  must  be  equally  an  educt  of  the  skin  of  young 
animals,  as  the  calf,  i.  e.  it  exists  in  the  skin  as  such,  and  is  not  produced 
from  the  action  of  boiling  water,  any  more  than  starch  is  produced 
from  grain  by  a  similar  process.  The  tissue  of  the  skin  is  closer  than  that 
of  the  air  bladder ;  hence  it  requires  a  longer  continuance  of  the  action  of 
water  to  separate  the  gelatin  from  the  other  principles.  Acetic  acid  will, 
however,  dissolve  gelatin  from  the  skin  in  the  cold,  and  tannic  acid  (in  tan- 
ning skins)  combines  with  the  gelatinous  tissues  in  the  cold,  to  form  leather. 
These  facts  show  correctly  and  truly  that  gelatin  exists  in  the  skin  as  an 
independent  principle,  like  albumen." 
Prof.  Lehman  (Physiolog.  Chem.),  who  takes  the  opposite  view,  is  on  the 
absurd  side.    Speaking  of  the  physiological  relations  of  gelatin,  he  says : 
"  Haller's  remark  :  Dimidium  corporis  humani  gluten  est,  now  requires  to  be 
mortified  to  the  assertion  that  half  of  the  solid  parts  of  the  animal  body  are 
convertible,  by  boiling  with  water,  into  gelatin;  for  actual  gelatin  is  not  con- 
tained in  the  animal  organism.  It  has  been  for  a  long  time  maintained  that 
gelatin  is  an  actual  constituent  of  the  swimming  bladder  of  certain  fishes 
