Am.  Jour.  Pharm.  ) 
Nov.  1,  1872.  J 
Varieties. 
519 
diately.  Several  applications  have  already  suggested  themselves  to  inventors  ; 
for  example,  to  render  paper  impermeable.  Sheets  of  paper  are  immersed  for 
a  few  moments  in  the  cupro-ammonium  solution,  then  pressed  between  rollers 
and  dried.  Paper  thus  treated  becomes  impermeable  even  to  boiling  water, 
and  water-tight  bags  could  be  constructed  of  such  material.  By  multiplying 
the  sheets  of  this  prepared  paper  and  rolling  them  together,  a  multitude  of 
objects  of  value  in  domestic  economy  and  the  arts  could  be  prepared.  Another 
property  of  the  cupro-ammonium  solution  is  to  impart  greater  tenacity  to  linen 
and  paper.  If  we  plunge  a  strip  of  paper,  the  tenacity  of  which  has  been  pre- 
viously tested,  into  the  ammoniacal  solution,  and  press  and  dry  it  between 
rollers,  it  will  be  found  to  have  increased  as  much  in  strength  as  parchment 
paper  prepared  by  immersion  in  sulphuric  acid.  Here,  again,  by  employing  a 
number  of  strips  of  paper  it  is  possible  to  form  a  band  nearly  as  strong  as 
leather,  and  it  is  a  question  whether  numerous  substitutes  for  leather  could  not 
be  made  in  this  way.  The  discovery  of  Schweitzer  has  already  been  applied  to 
the  manufacture  of  roofing,  pipes,  water  conductors,  safety  fuses,  hats,  boats 
and  clothing.  We  should  suppose  that  the  treatment  of  all  kinds  of  cellulose, 
wood,  grass,  linen,  cotton,  sawdust,  etc.,  as  a  preliminary  step  in  the  prepara- 
tion of  gun  cotton,  collodion  and  dualin,  would  prove  to  be  of  great  practical 
value.  Dr.  H.  Yogel  has  already  shown  that  precipitated  gun  cotton  affords 
the  best  film  for  photographic  purposes,  and  it  is  possible  that  by  dissolving 
cellulose  in  cupro-ammonium,  then  precipitating  it,  and  subsequently  convert- 
ing it  in  the  usual  manner  into  tri-nitro-cellulose,  or  gun-cotton,  a  very  superior 
article  could  be  obtained  from  inferior  stock.  There  are  various  ways  for  pre- 
paring the  cupro-ammonium.  One  is  to  dissolve  sulphate  of  copper  in  caustic 
ammonia  on  a  large  scale.  Copper  turnings  can  be  digested  in  caustic  ammo, 
nia  with  access  of  air,  until  a  concentrated  solution  is  obtained.  Only  a  con- 
centrated cupro-ammonium  solution  attacks  the  fiber,  and  when  the  liquid  is 
diluted  the  cellulose  is  at  once  precipitated.  The  discovery  of  Schweitzer 
opens  up  an  important  era  in  chemical  manufacture,  and  will  lead  to  many 
valuable  applications. — Jo  urn.  of  Applied  Chem.,  Sept.,  1872. 
Revaccination. — According;  to  a  statement  made  at  the  Statistical  Congress, 
held  this  year  in  St.  Petersburg,  the  total  number  of  deaths  from  smallpox  in 
the  Germau  army  during  the  recent  Franco-German  war  was  two  hundred  and 
sixty-three.  This  small  mortality  is  attributed  to  the  system  of  compulsory 
revaccination,  which  every  man  who  enters  the  army  must  undergo.  On  the 
other  hand,  in  the  French  army,  where  revaccination  is  not  compulsory,  the 
number  of  deaths,  as  stated  by  a  French  authority,  was  23,469.  This  terrible 
difference,  says  the  Wiener  Medtzin.  Wochenschr.,  must  puzzle  the  greatest 
opponents  of  vaccination. — Phila.  Med.  Times,  Oct.  26,  1872. 
Death  After  Taking  Chloral  Hydrate. — F.  Jolly  (Bayer.  Aerztl.  Intell.- 
Blatt.)  states  that,  in  the  course  of  two  years,  during  which  he  has  employed 
the  hydrate  of  chloral  in  the  treatment  of  the  insane,  he  had  met  with  two 
cases  of  sudden  death  following  its  use.  The  dose  was,  in  each  case,  below  the 
average,  and  the  chloral  was  chemically  pure.    The  patients,  during  life,  pre- 
