332 Proceedings of Royal Society of Edinburgh. [sess. 
parison. In a few instances, where an emetic action was suspected, 
the substances were administered to dogs also. In our experiments 
we used morphine hydrate dissolved in acetic acid and water, or 
morphine hydrochlorate, obtained from J. F. Macfarlan & Co., 
Edinburgh. 
Toxicity of Morphine. 
There are wide discrepancies in the statements regarding the 
minimum lethal dose of morphine in frogs, for, while Frohlich fixes 
it at O'Ql grin., Witkowski states that he has seen frogs recover 
after 0*05 grm. hydrochlorate. We found that it varied a good 
deal according to the condition of the frog and the season of the year, 
but that the ordinary lethal dose for a medium-sized frog is from 
3-5 centigrms. ( R . temporaria). The frog, after passing through the 
narcotic stage, remains tetanised or completely exhausted for several 
days, and ultimately dies of exhaustion. One to two centigrms. cause 
a marked narcotic stage, followed next day by an increase of reflexes, 
not amounting to tetanus. Five milligrms. caused very slight nar- 
cosis, which was not followed by any visible increase of reflexes. 
In rabbits also we could get no information regarding the mini- 
mum physiological dose, while the minimum lethal dose as given 
by different investigators (see Table) varied so much, that to 
Table showing the Minimum Lethal Dose of Morphine in Rabbits , 
as fixed by previous Experimenters. 
Name. 
Weight of Rabbit 
in Grms. 
Salt of Mor- 
phine used. 
Dose in 
Grms. 
Dose reckoned as 
Morphine Hydrate. 
Dose per Kilo. Body 
Weight. 
Remarks 
British Medical As- 
1360 
Hydrochlorate 
0-77 
0-627 
0-461 
Death with severe con- 
sociation Commis- 
vulsions in about one 
sion 
hour. 
Do. do. 
1360 
Meconate 
0-65 
0"456 
0-335 
Death with convulsions 
in 1 to 2 hours. 
Frohlich . 
Hydrochlorate 
0-3 
0-242 
2 Experiments only. 
Death in 10 and 24 
hours respectively. 
Koning* . 
330- 
Hydrochlorate 
0-47 
0-379 
0-66 
570 
1-15- 
Camus 
Hydrochlorate 
1-0 
0-806 
Death in 4j hours. 
Falck .... 
1250- 
Sulphate 
1 to 2 
0-799- 
0-63- 
Death in from 1 hour 36 
1500 
1-6 
1-08 
minutes to 3 hours 27 
minutes. 
Do 
1310 
Hydrochlorate 
1-0 
0-806 
0-61 
Death in 2 hours 45 
minutes. 
Quoted by Frohlich. 
