POISONS. yAK: 
120 per minute) together with a lessening of their 
force. On slightly increasing the dose, the pulsa- 
tions become languid, and prolonged pauses super- 
vene. If the dose is again somewhat strengthened, 
the pulsations become weaker and weaker, till they 
eventually cease altogether. The animal, however, 
is now in a condition of exalted reflex irritability , 
for its response to a single stimulus consists not 
merely, as in the unpoisoned animal, of a single 
spasm, but also, immediately after this, of a series 
of convulsive movements somewhat resembling 
swimming movements destitute of co-ordination. 
If the strength of the solution be now again 
increased, a stage of deeper anzesthesiation may be 
produced, in which the Medusa will only respond 
to each stimulation by a single spasm. In still 
stronger solutions, the only response is a single 
feeble contraction; while in a nearly saturated 
solution the animal does not respond at all. But 
even from a saturated solution Tiaropsis diade- 
mata will recover when transferred to unpoisoned 
water. 
4. Strychnia.—The species of covered-eyed Medusa 
which I shall choose for describing the action of 
strychnia is Cyanzea capillata, which is most admir- 
ably adapted for experiments with this and some 
cf the other alkaloid poisons, from the fact that in 
water kept at a constant temperature its pulsa- 
tions are as regular as are those of a heart. After 
Cyanzea capillata has been allowed to soak for ten 
minutes or so in a weak sea-water solution of 
strychnia, unmistakable signs of irregularity in the 
