144  Keeping  Qualities  of  Vaccine  Virus,     j  February Pi92im* 
days,  and  probably  a  week,  must  elapse  before  the  required  amount 
can  reach  him. 
In  looking  over  the  literature  on  the  subject,  we  find  very  few 
references.  Apparently  in  most  countries  which  have  direct 
communication  by  land  the  vaccine  virus  preserved  with  glyc- 
erin is  satisfactory  for  any  occasion,  and  no  further  steps  need 
be  taken  for  the  preservation  of  this  important  biologic  product. 
In  searching  for  data  concerning  the  dried  pulverized  vaccine, 
we  have  to  go  back  in  the  literature  to  1881  to  find  the  first  note 
on  the  subject.  Reissner  in  Darmstadt,  and  Frappoli  in  Italy, 
appear  to  have  been  the  first  ones  to  experiment  with  the  dry- 
ing of  vaccine  virus.  It  was  at  that  time  that  the  preservation 
of  vaccine  virus  for  wide  distribution  and  shipping  was  desirable; 
but  the  glycerinized  vaccine  virus,  as  introduced  by  Muller  about 
the  same  time,  became  supreme,  and  was  so  satisfactory  that 
no  further  attempts  were  made  to  dry  the  vaccine  virus.  As  far 
as  the  Philippine  Islands  is  concerned,  we  find  a  note  on  the 
"Preservation  of  vaccine  virus"  by  E.  H.  Ruediger  in  the  Bulletin 
of  the  Manila  Medical  Society,  August,  19 10. 
In  preparing  dried  vaccine  naturally  three  requirements  have 
to  be  fulfilled.  First,  the  drying  must  take  place  as  rapidly  and 
as  completely  as  possible,  and  without  the  application  of  artificial 
heat.  Second,  the  preservation  must  be  such  as  to  keep  the  powder 
in  absolutely  dry  condition;  it  must  be  kept  away  from  light,  par- 
ticularly sunshine,  and  from  heat.  Third,  the  bacterial  content  of 
the  dried  vaccine  must  be  considered;  in  the  absence  of  glycerin, 
which  in  the  glycerinized  vaccine  acts  not  only  as  a  preservative 
but  also  as  a  bactericide,  the  bacterial  content  in  the  dried  vaccine 
will  naturally  be  higher  than  in  the  glycerinized  vaccine. 
EXPERIMENTS  PROPER. 
The  vaccine  was  prepared  in  the  following  way:  The  pulp 
obtained  by  scraping  a  vaccinated  animal  was  ground  up  in  a 
sterile  mortar,  spread  over  a  large  surface  under  aseptic  con- 
ditions and  dried  rapidly  over  a  hygroscopic  chemical  in  vacuum, 
ground  up,  perfectly  dried,  and  kept  in  a  desiccator  at  room  tem- 
perature. Every  week  one  monkey  was  vaccinated  with  a  small 
portion  of  this  powder  and  kept  under  observation  in  order  to 
ascertain  whether  or  not  there  was  any  difference  in  the  develop- 
ment of  the  "take"  in  this  monkey  and  that  of  another  one,  used 
