Effect of Insulin on the Respiratory Exchange of Normal Animals 131
brought it to 0.060 per cent. within 45 minutes of the injection, after
which it fell more gradually, except for a temporary, partial recovery,
in i hour 45 minutes after the injection. In contrast to the previous
observation the blood-sugar continued to fall, until in 3 hours 40 minutes
after the injection convulsions became marked, having been preceded
by symptoms of hyperexcitability and muscular twitching. As in the
previous observation there was no change in respiratory volume or
rate, and only a trivial one in oxygen consumption during the period
of initial decline in blood-sugar, but these values then rose very rapidly
oJ B, M,IXJ A
~~~o~ *1O
ac 7~, "t
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~,,
'S/ :~~~~~~~~~~
,C Ex. A l / IN L I/ 10Pd/
4C \ 25/'
~o -__ AN0A /q Xe ECOM/xG
,,C4 6° 8 6 Y3 {«/cr sG- /; //S ut'Se
5cC INSVLLIN(2/I)
a O o u0 )J ld0 ILo I*o /(O i>d /00 Xe 2vo 7z,C ,? .t> JeI
7/-TPE 'N Pr'I/
FIc. 3.
when this had fallen below 0060 per cent., when the pulse also became
markedly accelerated. Shortly after, muscular twitchings were first
noted, the respiratory volume began to fall again, although the rate of
breathing continued to increase. There was a slight rise in R.'Q.
preceded by a fall.
The results of the two observations agree in showing that oxidative
processes become greatly stimulated after the blood-sugar is brought
down to between 50 and 60 mg. per cent., and that this is accompanied
by violent stimulation of the respiratory centre and by cardiac accelera-
tion. These changes occur before there is evidence of increased muscular
action, but they become very marked when this is visible.
These observations were repeated on another dog (B), weighing 17.3
kg., and the results are shown in figs. 3 and 4. In the observation on