30 
PRODUCTION  OF  LEECHES  IN  MICHIGAN. 
with  cobble  stones,  in  order  to  afford  a  refuge  for  the  leeches. 
The  water  exit  is  placed  about  ten  inches  below  the  top  edge  of 
the  tank,  which  edge  has  a  rim  of  boards  projecting  inwards,  all 
the  way  around  nailed  to  it.  This  is  all  the  apparatus  required, 
and  they  need  but  very  little  attention.  A  few  frogs  thrown  in 
once  a  week  will  supply  five  thousand  of  them  with  food  suffi- 
cient. In  winter  they  become  torpid,  and  the  tank  is  allowed 
to  freeze  over  and  so  remain  till  spring. 
They  produce  their  eggs  during  the  months  of  June  and  July, 
and  the  leech  is  matured  in  about  two  years.  Their  age  when 
subject  to  ordinary  care  is  about  fifteen  years. 
When  applied  they  bite  readily,  and  draw  about  two  drachms 
of  blood,  the  flow  of  which,  however,  is  to  be  excited  in  the  usual 
ways. 
Those  parts  to  which  leeches  are  to  be  applied  should  be  well 
cleansed  from  smell  or  perspiration,  and  they  are  best  used  by 
putting  the  requisite  number  into  a  suitable  sized  cupping  glass 
partly  filled  with  water,  and  applying  the  edges  of  the  cup  closely 
to  the  part  to  be  leeched ;  after  they  have  taken  hold,  the  cup 
may  then  be  gently  removed. 
The  naturalized  leech  is  hardy,  rather  small,  (from  one  to  two 
and  a  half  inches  long,)  and  very  active  ;  those  produced  from 
the  variety  brought  from  Pennsylvania  (a  specimen  of  which  is 
herewith  submitted)  are  of  a  velvety  olive  green  color  upon  the 
dorsal  surface,  with  three  longitudinal  rows  of  spots ;  the  centre 
one  orange  colored,  the  others  black ;  the  belly  is  of  a  rusty 
orange  spotted  with  black. 
The  grey  leech  of  Michigan,  the  best  of  those  indigenous  to 
the  State,  is  of  a  uniform  grey  color,  extremely  thin  or  flat, 
peculiar  in  its  motions,  is  with  difficulty  induced  to  draw,  though 
its  bite  is  unaccompanied  with  any  pain ;  the  eggs  of  the  leech, 
instead  of  being  left  to  take  care  of  themselves,  as  in  the  case  of 
the  other  leeches,  are  attached  to  the  belly,  as  are  the  young 
leeches  for  some  time  after  their  development. 
The  low  price  at  which  these  leeches  can  be  produced  renders 
their  aid  available  to  the  poorest ;  and  while  by  cheapening 
them,  they  are,  by  increased  demand,  rendered  a  greater  source 
of  pecuniary  profit,  they  will  cost  the  producer  nothing  but  a  little 
time  and  patience. 
From  the  Proceedings  of  the  American  Pharmaceutical  Association — 1857. 
