Tuberculosis. 
32 
matter  how  extensive  the  disease  may  be  in  other  parts  of 
the  cow’s  body.  It  is  a well-known  fact  that  in  advanced 
cases  of  tuberculosis  in  cows  the  uterus  often  becomes  involved, 
whereas  in  the  human  and  other  species  than  the  bovine 
tuberculosis  of  the  uterus  is  a very  rare  condition.  This  affords 
an  explanation  of  the  greater  frequency  of  congenital  tuber- 
culosis in  the  bovine  than  in  the  human  species. 
A point  of  considerable  importance  in  connection  with  the 
alleged  frequency  of  congenital  tuberculosis  remains  to  be 
examined.  In  what  precedes  the  manner  in  which  the  disease 
is  ti’ansmitted  from  the  cow  to  the  foetus  has  been  explained, 
but  those  who  have  contended  that  congenital  tuberculosis  is 
common  have  never  admitted  that  infection  is  from  the  female 
parent  only.  On  the  contrary,  it  has  often  been  held  that  the 
disease  is  quite  as  likely  to  be  passed  on  in  this  way  from  the 
father,  and  some  still  believe  that  such  transmission  plays  an 
important  part  in  the  spread  of  tuberculosis  among  cattle. 
Against  such  a belief  it  may  be  pointed  out  in  the  first  place 
that  it  is  only  by  ignoring  the  fact  that  tuberculosis  is  a 
contagious  disease,  liable  to  be  contracted  at  any  time  after 
birth,  that  any  one  can  perceive  the  least  occasion  for  surmising 
that  tuberculous  male  parents  hand  on  the  actual  disease  to 
the  foetuses  which  they  beget.  A large  proportion  of  the 
calves  got  by  a particular  bull  may  before  they  reach  maturity 
be  proved  to  be  tuberculous,  but  since  there  are  in  almost 
every  herd  opportunities  for  infection  after  birth  this  fact 
does  not  in  the  least  justify  the  conclusion  that  these  animals 
were  born  tuberculous,  or  that  the  sire  was  the  source  of 
their  infection. 
But  if  any  cases  of  congenital  tuberculosis  among  calves 
are  attributable  to  the  bull,  they  are  all  included  in  the 
something  less  than  1 per  cent,  which  constitutes  the  total 
proportion  of  calves  found  by  post-mortem  examination  to  be 
tuberculous  at  birth.  It  therefore  follows  that  the  slaughter- 
house statistics  previously  referred  to  are  conclusive  evidence 
against  the  view  that  the  transmission  of  the  actual  disease 
from  the  bull  to  the  foetus  is  a common  occurrence.  Further- 
more, it  has  already  been  shown  that  when  a calf  is  born 
tuberculous  the  fact  can  generally  be  accounted  for  without 
incriminating  the  bull,  numerous  observations  making  it 
highly  probable  that  the  foetus  was  infected  through  having 
been  developed  in  a tuberculous  uterus. 
Since  it  must  be  held  to  be  proved  that  if  the  disease  is 
ever  transmitted  from  the  male  parent  the  occurrence  is 
exceedingly  rare,  the  question  is  now  devoid  of  any  practical 
importance.  It  may  be  observed,  however,  that  there  is  no 
real  evidence  to  show  that  the  disease  is  ever  transmitted  in 
