﻿30 
  INTRODUCTION. 
  

  

  IV. 
  Dermal 
  Secretion. 
  

  

  The 
  skin 
  of 
  the 
  dorsal 
  sui'face 
  of 
  all 
  Batrachians 
  is, 
  

   as 
  we 
  have 
  seen, 
  studded 
  with 
  glands 
  and 
  follicles. 
  

   In 
  various 
  species, 
  of 
  which 
  our 
  Bufones 
  are 
  good 
  

   examples, 
  some 
  of 
  the 
  larger 
  glands 
  appear 
  as 
  very 
  

   prominent 
  warts 
  pierced 
  with 
  wide 
  pores, 
  especially 
  a 
  

   large 
  mass 
  situated 
  on 
  each 
  side 
  of 
  the 
  back 
  of 
  the 
  

   head 
  behind 
  the 
  eyes, 
  which 
  has 
  received 
  the 
  mis- 
  

   nomer 
  of 
  parotid, 
  a 
  name 
  now 
  generally 
  changed 
  to 
  

   parotoid 
  gland. 
  These 
  glands 
  secrete, 
  more 
  or 
  less 
  

   abundantly 
  according 
  to 
  the 
  species, 
  a 
  viscid 
  or 
  milky 
  

   more 
  or 
  less 
  and 
  variously 
  odorous 
  fluid, 
  which 
  is 
  

   exuded, 
  when 
  the 
  animal 
  is 
  disturbed, 
  by 
  means 
  of 
  the 
  

   contraction 
  of 
  small 
  muscles 
  disposed 
  in 
  the 
  skin 
  

   around 
  the 
  glands. 
  If 
  the 
  larger 
  glands 
  be 
  pressed 
  

   or 
  subjected 
  to 
  an 
  electric 
  current 
  the 
  secretion 
  is 
  

   squirted 
  out 
  with 
  great 
  force, 
  and 
  sometimes 
  to 
  a 
  

   considerable 
  distance. 
  Kobert 
  recommends, 
  as 
  the 
  

   best 
  means 
  of 
  obtaining 
  an 
  abundant 
  supply 
  of 
  toad- 
  

   poison, 
  the 
  subcutaneous 
  injection 
  of 
  a 
  small 
  dose 
  of 
  

   chloride 
  of 
  barium 
  ; 
  after 
  a 
  few 
  minutes 
  the 
  animal 
  is 
  

   so 
  covered 
  with 
  its 
  secretion 
  as 
  to 
  appear 
  as 
  if 
  coated 
  

   with 
  whitewash. 
  The 
  object 
  of 
  the 
  secretion 
  is 
  to 
  

   o-uard 
  Batrachians 
  from 
  the 
  attacks 
  of 
  various 
  enemies. 
  

  

  o 
  ... 
  

  

  A 
  dog 
  will 
  not 
  often 
  repeat 
  the 
  experiment 
  of 
  seizing 
  

   a 
  toad; 
  the 
  signs 
  of 
  pain 
  which 
  it 
  evinces 
  after 
  the 
  

   poisonous 
  fluid 
  has 
  come 
  into 
  contact 
  with 
  its 
  mouth 
  

   is 
  familiar 
  to 
  most 
  of 
  those 
  who 
  have 
  kept 
  young 
  

   dogs 
  in 
  the 
  country. 
  That 
  excellent 
  Hungarian 
  

   naturalist, 
  Prof. 
  v. 
  Mehely, 
  relates 
  the 
  serious 
  effects 
  

   of 
  the 
  poison 
  of 
  Biifo 
  viridis 
  on 
  a 
  small 
  terrier 
  which 
  

   accompanied 
  him 
  on 
  a 
  collecting 
  excursion. 
  A 
  large 
  

   toad, 
  found 
  under 
  a 
  stone, 
  was 
  at 
  once 
  attacked 
  by 
  

   the 
  dog, 
  but 
  no 
  sooner 
  seized 
  was 
  let 
  go 
  again 
  with 
  

   signs 
  of 
  great 
  repulsion 
  ; 
  the 
  toad 
  had 
  instantly 
  become 
  

   covered 
  with 
  a 
  thick 
  white 
  secretion. 
  The 
  dog 
  ap- 
  

   proached 
  it 
  once 
  more 
  and 
  then 
  withdrew, 
  sneezing 
  and 
  

  

  