﻿1875.] 
  Dr. 
  F. 
  W. 
  Pavy 
  on 
  the 
  Production 
  of 
  Glycosuria. 
  539 
  

  

  ment 
  was 
  made 
  at 
  the 
  half-moon, 
  when 
  the 
  moon 
  was 
  high 
  up, 
  so 
  that 
  the 
  

   light 
  fell 
  obliquely 
  on 
  the 
  window 
  and 
  did 
  not 
  shine 
  directly 
  on 
  the 
  

   selenium. 
  

  

  On 
  throwing 
  the 
  moonlight 
  on 
  the 
  selenium 
  by 
  means 
  of 
  a 
  plane 
  mirror, 
  

   the 
  needle 
  was 
  at 
  once 
  deflected 
  20 
  divisions 
  of 
  the 
  scale 
  ; 
  on 
  placing 
  the 
  

   mirror 
  outside 
  the 
  window 
  so 
  as 
  to 
  send 
  the 
  moonlight 
  perpendicularly 
  

   through 
  the 
  window 
  on 
  the 
  selenium, 
  the 
  deflection 
  of 
  the 
  needle 
  was 
  40 
  

   divisions. 
  The 
  window 
  was 
  kept 
  closed 
  during 
  these 
  experiments. 
  

  

  On 
  another 
  evening 
  when 
  the 
  moon 
  shone 
  very 
  obliquely 
  on 
  the 
  window, 
  

   and 
  the 
  selenium 
  was 
  exposed 
  on 
  the 
  inside 
  of 
  the 
  window 
  directly 
  

   to 
  the 
  moonlight, 
  the 
  needle 
  was 
  deflected 
  100 
  divisions 
  of 
  the 
  scale, 
  

   and 
  the 
  deflection 
  increased 
  to 
  150 
  divisions 
  after 
  exposure 
  for 
  about 
  

   3 
  minutes. 
  

  

  The 
  change 
  in 
  the 
  resistance 
  of 
  the 
  selenium 
  was 
  from 
  60,000 
  to 
  70,000 
  

   ohms. 
  

  

  These 
  experiments 
  show 
  that 
  the 
  action 
  on 
  the 
  selenium 
  is 
  due 
  princi- 
  

   pally, 
  if 
  not 
  entirely, 
  to 
  radiations 
  belonging 
  to 
  the 
  visible 
  part 
  of 
  the 
  

   spectrum. 
  Light 
  rays 
  of 
  all 
  kinds, 
  particularly 
  the 
  greenish 
  yellow, 
  pro- 
  

   duce 
  an 
  instantaneous 
  effect 
  followed 
  by 
  a 
  more 
  or 
  less 
  gradual 
  effect, 
  

   which 
  continues 
  to 
  increase 
  during 
  exposure 
  for 
  several 
  minutes. 
  

  

  These 
  facts 
  suggest 
  two 
  hypotheses 
  as 
  possible 
  explanations, 
  which 
  may 
  

   help 
  as 
  guides 
  in 
  further 
  experiments, 
  but 
  which 
  cannot 
  be 
  accepted 
  

   as 
  proved 
  without 
  further 
  evidence. 
  

  

  (1) 
  That 
  the 
  light 
  falling 
  on 
  the 
  selenium 
  causes 
  an 
  electromotive 
  

   force 
  in 
  it, 
  which 
  opposes 
  a 
  battery-current 
  passing 
  through 
  it, 
  the 
  effect 
  

   being 
  similar 
  to 
  the 
  effect 
  due 
  to 
  polarization 
  in 
  an 
  electrolyte. 
  

  

  (2) 
  That 
  the 
  light 
  falling 
  on 
  the 
  selenium 
  causes 
  a 
  change 
  on 
  its 
  sur- 
  

   face 
  akin 
  to 
  the 
  change 
  which 
  it 
  produces 
  on 
  the 
  surface 
  of 
  a 
  phospho- 
  

   rescent 
  body, 
  and 
  that 
  in 
  consequence 
  of 
  this 
  change 
  the 
  electric 
  current 
  

   is 
  enabled 
  to 
  pass 
  more 
  readily 
  over 
  the 
  surface 
  of 
  the 
  selenium. 
  

  

  XIII. 
  " 
  On 
  the 
  Production 
  of 
  Glycosuria 
  by 
  the 
  Effect 
  of 
  oxy- 
  

   genated 
  Blood 
  upon 
  the 
  Liver." 
  By 
  F. 
  W. 
  Pavy, 
  M.D., 
  F.R.S. 
  

   Received 
  June 
  17, 
  1875. 
  

  

  In 
  a 
  communication 
  on 
  " 
  Lesions 
  of 
  the 
  Nervous 
  System 
  producing 
  

   Diabetes," 
  presented 
  to 
  the 
  Royal 
  Society 
  in 
  1859 
  (Proc. 
  Roy. 
  Soc. 
  vol. 
  

   x. 
  1859-60), 
  I 
  made 
  known 
  that 
  division 
  of 
  certain 
  parts 
  of 
  the 
  sympa- 
  

   thetic 
  system 
  occasioned 
  the 
  presence 
  of 
  sugar 
  in 
  the 
  urine. 
  The 
  effect 
  

   of 
  puncturing 
  the 
  floor 
  of 
  the 
  fourth 
  ventricle 
  (Bernard's 
  celebrated 
  

   experiment) 
  had 
  been 
  for 
  some 
  time 
  previously 
  familiar 
  to 
  physiologists 
  ; 
  

   but 
  nothing 
  had 
  been 
  ascertained 
  about 
  the 
  production 
  of 
  diabetes 
  by 
  

   lesions 
  of 
  the 
  sympathetic, 
  until 
  my 
  experiments 
  upon 
  the 
  subject 
  were 
  

   conducted 
  ; 
  and 
  it 
  was 
  in 
  attempting 
  to 
  discover 
  the 
  channel 
  through 
  

  

  