LIFE-TESTS. 
§ 34 -] 
47 
be recognised by the fact that contraction may be excited by mechanical and electrical 
stimuli or by the application of atropine solution ; the latter paralyses the inhibitory 
nervous centres, and therefore sets the mechanism going again. The diastole of 
paralysis is the most frequent form of death. It may readily be distinguished from the 
muscarine diastole ; for in muscarine diastole the heart is full of blood and larger 
than normal, but in the paralytic form the heart is not fully extended ; although, if 
normal blood replace that which is poisoned, the beats may be restored for a short 
time, the response is incomplete, and the end is the same ; besides which, atropine 
does not restore the beats. The diastole of paralysis may depend on paralysis of the 
so-called excito-motor ganglia (as with iodal), or on paralysis of the muscular 
structure (as with copper). 
The heart at the height of the poisoning stops in systole. 
2 . Arrest in Systole. —The systole preceding the arrest is far stronger than 
normal, the ventricle often contracting up into a little lump. Contraction of this 
kind is specially to be seen in poisoning by digitalis. In poisoning by digitalis the 
ventricle is arrested before the auricle ; in muscarine poisoning the auricle stops before 
the ventricle. If the reservoir of Williams’ apparatus is raised so as to increase the 
pressure within the ventricle the beat may be restored for a time, to again cease. 
A frog’s heart under the influence of any poison may be finally divided into 
pieces so as to ascertain if any parts still contract ; the significance of this is, that 
the particular ganglion supplying that portion of the heart has not been affected : the 
chief ganglia to be looked for are Remak’s, on the boundary of the sinus and auricle ; 
Ludwig’s, on the auricle and the septum of the auricle ; Bidder’s, on the atrioventri¬ 
cular border, especially in the valves ; and Dogiel’s ganglion, between the muscular 
fibres. According to Dogiel, poisons acting like muscarine affect every portion of the 
heart, and atropine restores the contractile power of every portion. 
Jacobi’s Apparatus. —Glass canulas are introduced into the left vena cava and 
aorta respectively, the other big vessels being ligatured ; the arrangement is as in the 
figure. The one canula is connected with an india-rubber tube a, attached to Marriott’s 
flasks by means of a Y-piece ; the other to a T-piece T, connected on the one side to 
a small mercury manometer; the limb of the manometer nearest the T-piece is con¬ 
nected with a pressure tube S ; the other limb of the manometer is, as shown, pro¬ 
vided with a recording apparatus which draws a curve on the revolving cylinder C ; 
the other side of the T-piece consists of a tube, connected with a wider tube W ; into 
this fits a glass rod, which can be pushed in and out; the glass rod is so arranged as 
to leave a fine capillary slit; the farther this rod is pulled out the easier the fluid 
drops into V, the farther it is pushed in the slower the liquid drops, and therefore 
