580  Therapeutic  Application  of  the  X-Rays.  {A?ecSet?ff' 
his  opinion  or  advice  by  customers  or  friends,  and  if  he,  as  he  should 
be,  is  able  to  speak  intelligently  on  the  subject,  he  will  probably 
have  sufficient  influence  to  induce  the  patient  to  submit  to  the 
advice  or  directions  of  his  family  physician.  That  the  X-rays  have 
effected  cures  that  appear  to  border  on  the  wonderful  cannot  be 
denied.  But  it  is  also  true  that  the  conditions  under  which  these 
cures  have  been  effected  cannot  readily  be  duplicated  in  every 
instance.  We  have  here  but  another  illustration  of  the  fact,  that 
while  success  in  any  field  of  human  achievement  is,  as  a  rule,  freely 
reported,  corresponding  failures  also  happen  but  are  given  little  or 
no  publicity,  and  usually  find  their  way  to  our  knowledge  by  disap- 
pointing personal  experiences. 
To  get  a  better  idea  of  the  action  of  the  X-rays  it  will  be  neces- 
sary to  follow  in  outline  the  development  of  our  knowledge  of  the 
subject. 
As  is  well  known,  the  announcement  of  the  discovery  of  these 
physical  phenomena  was  made  by  Wilhelm  Conrad  Roentgen,  at 
Wiirzburg,  during  December,  1895,  and  Dv  mm  named  the  X  or 
unknown  rays.  These  rays  are  caused  by  the  discharge  of  a  high 
tension  current  of  electricity  through  a  suitable  vacuum  tube,  and 
may  be  defined  as  a  a  form  of  energy  that  will  penetrate  otherwise 
opaque  bodies,  and  cause  certain  chemical  substances  to  fluoresce, 
or  they  will  affect  photographic  plates  very  much  similar  to  ordi- 
nary actinic  light."  All  of  these  properties  had  been  observed  by 
Roentgen  before  he  announced  his  discovery,  and  practically  the 
only  new  discovery  that  has  been  added  is  the  fact  that  these  rays 
are  practically  conductors  of  electricity,  and  have  the  additional 
property  of  dispersing  negative  charges  on  insulated  surfaces,  and 
then  charging  these  same  surfaces  with  a  positive  charge. 
The  fact  that  the  X-rays  had  the  property  of  penetrating  other- 
wise opaque  bodies  was  immediately  made  use  of  to  a  considerable 
extent,  largely  with  a  view  of  exploiting  the  possibilities  of  their 
application  for  scientific  investigations.  Shortly  after  the  first 
announcement  of  the  discovery  of  these  rays,  there  appeared  in 
the  medical,  as  well  as  lay-press,  accounts  of  peculiar  secondary 
effects  that  were  occasioned  by  a  prolonged  exposure  to  the  excited 
vacuum  tube.  Chief  among  these  was  a  severe  dermatitis,  or 
inflammation  of  the  skin,  simulating  a  very  severe  case  of  sunburn. 
In  cases  where  the  head  and  face  had  been  exposed  this  was  some- 
