EROSION  OF  LEAD  BY  INSECTS. 
71. 
away.  The  sensitive  nerves  are  much  less  affected  than  by 
morphia,  and  no  paralysis  is  observed  when  the  animal  awakens. 
Narceia  seems  to  produce  the  combined  effects  of  morphia 
and  codeia,  and  appears  to  be  the  most  strongly  soporific  prin- 
ciple in  opium.  The  animal  sleeps  more  profoundly,  but  is  not 
so  much  stupified  as  with  morphia  ;  and  at  the  same  time  is 
not  so  excitable  as  when  under  the  influence  of  codeia.  It 
quickly  returns  to  its  natural  state,  and  on  awaking  is  neither 
frightened  nor  savage. 
All  these  effects  have  been  confirmed  by  repeated  experiments 
on  all  available  animals,  and  they  appear  to  be  constant  and 
invariable. 
Coming  to  the  poisonous  effects  of  the  alkaloids,  the  author 
informs  us  that  thebaina  is  the  most  active  poison.  A  deci- 
gramme of  the  hydrochlorate  of  this  alkaloid  injected  into  the 
veins  of  a  dog  killed  it  in  five  minutes  ;  but  it  is  stated  that 
two  grammes  of  hydrochlorate  of  morphia  injected  into  the 
veins  of  a  dog  of  the  same  size  did  not  cause  death.  There 
must,  we  think,  be  some  mistake  here ;  two  decigrammes,  per- 
haps, are  meant.    Codeia  stands  intermediate  as  a  poison. 
Thebaina  also  stands  first  as  the  most  powerful  agent  in  pro- 
ducing convulsions. 
The  inquiry  which  M.  Bernard  has  thus  opened  is  very  large 
and  important,  and  will,  no  doubt,  be  followed  out  with  all  the 
skill  and  care  for  which  he  is  distinguished. — Comptes  Rendus, 
and  Chem.  News,  Sept.  10,  1864. 
EROSION  OF  LEAD  BY  INSECTS. 
A  letter  to  the  Times,  signed  "Y,"  states  that  the  erosion  of 
lead  by  certain  species  of  insects  is  not  generally  known,  and 
may  be  extremely  mischievous.  Not  long  ago  it  attracted  the 
attention  of  the  French  Academy  of  Sciences,  and  several  com- 
munications upon  it  have  been  .published  in  their  proceedings, 
the  Comptes  Rejndus.  In  1858  Marshal  Vaillant  exhibited  to 
the  Academy  leaden  bullets  brought  back  from  the  Crimea,  in 
some  of  which  the  larvae  of  insects  had  excavated  circular  pas- 
sages three  or  four  millimetres  in  diameter ;  but  nothing  of  the 
kind  had  been  detected  in  the  cartridges  of  the  Russian  army 
