68 
I Tie  Physiology  of  Stock-Breeding . 
No  apology  is  needed,  therefore,  for  publishing  in  an 
agricultural  journal  an  article  dealing  with  the  bearing  of 
recent  physiological  observations  upon  the  practice  of  animal 
breeding.  But  in  order  to  render  these  intelligible  to  the 
reader,  it  is  necessary  to  go  over  old  ground,  to  restate  various 
fundamental  facts  which  are  sometimes  lost  sight  of,  and 
incidentally  to  revise  certain  conclusions  which  often  pass 
current  at  the  present  time. 
Ova  and  Spermatozoa. 
The  development  of  every  animal  (at  least  among  the  higher 
forms  of  life)  is  initiated  by  the  conjugation  of  a female  germ 
cell  or  ovum  with  a male  germ  cell  or  spermatozoon.  The  pro- 
duct of  union  or  fertilised  ovum  in  virtue  of  this  act  of 
conjugation  is  endowed  with  a new  vitality,  whereby  it  is 
rendered  capable  of  undergoing  that  long  series  of  cell  divisions 
which  culminates  in  the  complete  development  of  a new  indi- 
vidual, bearing  a more  or  less  close  resemblance  to  the  sire  and 
dam,  from  which  the  spermatozoon  and  ovum  were  respectively 
derived.  In  the  act  of  copulation  the  spermatozoa,  which 
swim  freely  in  the  seminal  fluid  of  the  male,  are  injected 
through  the  penis  into  the  female  genital  passages  (vagina  and 
uterus).  In  the  ram,  as  I have  shown  elsewhere,^  the  penis  is 
provided  with  a long  tubular  filiform  appendage  composed 
largely  of  erectile  tissue,  and  through  this  prolongation  the 
spermatozoa  must  pass  before  being  ejaculated.  This  fact  is 
taken  advantage  of  by  ram  traders  when  wishing  to  discard 
tups  for  breeding  purposes.  The  filiform  appendage  is  removed 
before  the  ram  is  sent  to  market.  Many  novices  have  been 
deceived  by  this  practice,  called  “ worming  for  such  sheep  are 
bought  by  unscrupulous  dealers,  in  open  mai’ket,  who  pass 
them  on  to  the  unwary  as  sound  sires,  though  they  them- 
selves have  only  paid  a “butcher’s”  price  for  them.  The  erectile 
character  of  this  structure  would  seem  to  indicate  that  it  is 
inserted  into  the  mouth  of  the  uterus  (womb  or  “ bed  ”)  so  as 
Fig.  1.— Terminal  portion  of  ram’s  penis  showing  filiform  prolongation. 
(About  i natural  size). 
to  ensure  the  passage  of  the  spermatozoa  into  that  organ,  and 
not  merely  into  the  outside  chamber  or  vagina.  It  is  clear, 
therefore,  that  any  injury  to  this  somewhat  delicate  penile 
appendage  may  impair  the  fertility  of  the  ram. 
' Marshall:  “The  Copulatory  Organ  in  the  Sheep,”  Anatomischer  Anzeiger, 
Vol.  20,  1901. 
