504  tnseds  Destructive  to  Books.      .  {^S;/eZ;rfmT" 
not  always,  as  in  the  case  of  certain  bacteria,  who  from  their  known 
powxr  to  withstand  a  high  degree  of  heat,  are  popularly  called  heat- 
lovers.  They  have  even  stood  the  high  temperature  of  steam  for  a 
number  of  hours.  But  aside  from  the  imago  state  of  the  insect,  the 
egg,  in  which  the  embryo  passes  through  its  various  stages,  has  been 
overlooked,  and  experiments  properly  conducted  will  prove  them 
capable  of  withstanding  a  temperature  very  much  above  that  which 
the  scientist  of  to-day  has  knowledge. 
Anyone  caring  to  investigate  the  life  in  the  paste  may  easily  do 
so  in  the  following  way :  Boil  the  flour  in  the  usual  manner,  adding 
the  glue  for  the  binder,  and  after  allowing  the  mass  to  cool,  let  it 
stand  in  a  dark,  damp  place.  After  it  has  become  sour,  it  will  be 
found  that  nature  will  again  produce  the  same  forms  from  it  as  she 
did  when  it  was  in  the  form  of  flour.  Naturally,  to  give  conclusive 
evidence,  care  must  be  taken  to  see  that  no  insects  are  allowed  to 
gain  access  to  the  paste  from  the  outside,  so  as  to  avoid  any  possi- 
bility of  their  laying  their  eggs  in  the  substance. 
Bindings:  Wood  Bindings. — Books  that  are  bound  with  wood 
covers  are  always  subject  to  the  borings  of  the  insects  that  lived  on 
the  species  of  trees  from  which  the  boards  are  made,  especially  if 
the  atmosphere  is  saturated  with  moisture,  this  being  due  to  the 
porous  nature  of  the  wood.  Take  the  point  of  a  needle,  touch  the 
wood,  and  you  find  that  it  gives,  showing  that  it  is  composed  of  cells 
containing  gases.  They  are  not  only  subject  to  attacks  from  with- 
out, but  also  from  within ;  i.e.,  larvae  hatching  from  eggs  that  were 
deposited  in  the  tree  before  it  was  made  into  lumber.  The  early 
stages  of  a  number  of  species  of  wood-destroying  insects  take  quite 
a  long  period  to  evolve. 
The  insects  destroying  wood  bindings  are  species  of  Bostrychidce 
and  some  of  the  Scolytidce.  One  species  of  Ceramhycidce  has  been 
named  as  causing  trouble,  and  as  a  large  proportion  of  the  species 
of  this  family  are  wood-borers,  other  species  will  likely  be  found  to 
tunnel  these  covers. 
Bindings:  Leather  Bindings. — The  so-called  dry  rot  of  leather 
bindings  said  to  be  caused  by  the  fumes  in  the  air,  especially  where 
gas  is  used  for  lighting  purposes,  is  also  found  to  take  place  with 
leather-bound  books  that  have  not  been  exposed  to  such  chemicals. 
Investigation  will  prove  that  instead  of  gases  being  the  destructive 
agency,  minute  forms  of  life  alone  are  the  cause. 
Another  subject  for  future  research  is  the  cause  of  certain  round 
