20 
Books  as  a  Source  of  Disease. 
/Am.  Jour.  Pharm. 
I    January,  1914. 
In  certain  cases  the  period  of  incubation,  if  it  can  be  so  called,  is  long-, 
in  others  it  is  short;  the  difference  is  the  result  of  the  different 
degrees  of  preparedness  of  the  contagious  matter,  and  I  personally 
believe  that  the  health  of  the  person  infected  has  most  to  do  with  the 
appearance  or  non-appearance  of  a  disease." 
The  length  of  time  that  the  different  pathogenic  bacteria  can 
withstand  drying  varies  greatly.  Krausz  placed  bacteria  from  48- 
hour  old  cultures  in  books  and  kept  them  in  the  dark  at  room  tem- 
perature. He  found  that  cholera  lived  only  40-95  days  and  tubercle 
bacilli  80-103  days.  Other  investigations  confirm  his  results  except 
in  the  cases  of  tuberculosis  and  diphtheria.  Abel  found  that  diph- 
theria bacilli  retained  their  virulency  on  toys  for  six  months  and 
this  is  the  length  of  time  that  Von  Scham  gives.  Lion  and  Von 
Schab  both  say  that  tubercle  bacilli  withstand  drying  from  six  to 
nine  months. 
The  number  of  bacteria  that  may  be  found  on  much-used  books 
was  investigated  by  Lion.  A  novel  from  a  public  library  varied  from 
250  .bacteria  per  100  square  centimetres  on  the  middle  of  a  clean 
page  to  1,250,  1,875,  and  3,350  on  the  dirty  edges.  A  college  atlas 
showed  from  650  to  1,075  Per  100  square  centimetres;  an  anatomy 
book  2,275  to  3,700.  The  bindings  were  by  far  the  richest  in  bacteria, 
yielding  on  an  average  of  7,550  per  square  centimetre. 
As  to  the  pathogenic  bacteria  that  may  occur  on  books,  the  follow- 
ing investigations  are  of  great  interest.  Krausz  inoculated  seven 
guinea  pigs  with  dirty  pieces  of  paper  from  much-used  books  and 
they  all  died  of  peritonitis.  The  eighteen  inoculated  with  pieces  from 
clean  books  remained  healthy.  Du  Cazal  and  Catrin  found  Staphy- 
lococcus pyogenes  on  an  old  book  in  a  hospital.  Most  striking  of  all 
are  Mitelescu's  experiments.  He  took  60  much-used  books  that  had 
been  in  a  public  library  from  six  months  to  two  years ;  he  cut  out  the 
dirtiest  parts,  soaked  them  in  salt  solution,  centrifuged  the  liquid 
and  inoculated  guinea  pigs  with  the  sediment.  Nineteen  died  of 
septicemia,  and  twelve  of  streptococcus  infection.  He  repeated  the 
experiment  with  thirty-seven  books  from  three  to  six  years  old. 
Fourteen  of  the  guinea  pigs  died  of  septicemia,  and  fifteen  contracted 
tuberculosis.  The  damp  dirt  on  the  older  books  was  a  good  medium 
for  tubercle  bacilli. 
The  following  abstracts  are  taken  from  the  report  made  to  the 
Board  of  Trustees  of  the  Chicago  Public  Library  upon  books  in  that 
