PROGRESS OF MICROSCOPICAL SCIENCE. 
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the two leaves in water and they partially re-expanded. I thought 
that the whitened glands were perhaps killed ; but those of one leaf 
which I tried with carbonate of ammonia absorbed it, and the pro- 
toplasm was affected in the usual manner. I am very much surprised 
at the action of the poison on the viscid secretion from the glands, 
which it coagulates into threads and bits of membrane, with much 
granular matter. Have you observed whether the poison affects in 
any marked manner mucus or other such secretions ? " 
Action of Cohra-poison on Muscle. 
June 29, 1874. — A standard solution of cobra-poison,* 03 gramme 
to 4-6 cubic centims. of water, was prepared. 1.25 p.m. The gas- 
trocnemius of a frog was separated and immersed in this solution in 
a watch-glass; it immediately contracted considerably. 1.30. The 
muscle contracts with current at 11. 1.45. The muscle has lost its 
irritability ; does not respond to the strongest current. At the same 
time (1.25 p.m.) the gastrocnemius from the other leg of the same 
frog immersed in water. Did not immediately contract like that 
placed in the poisoned solution. 1.30. Contracts strongly to current at 
15 c. m. of Du Bois Eeymond's coil, more than the poisoned muscle 
at 11, at the same moment. 1.45. Contracts distinctly at 11, whilst 
the poisoned muscle has lost all irritability. From this it is evident 
that the poison first stimulates the muscular fibre to contract, but 
rapidly afterwards destroys its irritability. The gastrocnemii of a 
frog were again treated in the same way as in the previous experiment, 
with precisely the same results. 
June 28. — Made several experiments with cobra-poison on ciliated 
epithelium of frog's mouth, and found that it at first accelerated, then 
destroyed, the action of the cilia. 
November. — A little cobra-poison, dissolved in water, was added 
to water containing some cells scraped from the mantle of a fresh- 
water mussel. Among these was a large ciliated cell, which, before 
the addition of the poison, had been moving slowly, although its 
cilia were moving actively. Immediately after the addition of the 
poison the cell began to spin round on its own axis with extraordinary 
rapidity. In about three or four minutes its motions began to be 
languid, the ciliary motion ceased, the cell itself elongated, con- 
tracted, and then slowly resumed its former shape and became per- 
fectly motionless. Water from the interior of a fresh-water mussel, 
and containing two specimens of Paramcecium in active motion, was 
examined. They were rotating with great rapidity. A little cobra- 
poison diluted with water was added. Three minutes after the addi- 
tion one was discovered with both the cilia and cell-body perfectly 
still. The cilia of the other were still, but the cell-body was con- 
tracted. In about half a minute more it expanded to its normal size 
and then remained perfectly still. 
A piece taken from the mantle of a fresh-water mussel was placed 
on the slide and examined at the end of about half an hour. Active 
ciliary motion could be observed both in the fringe of the mantle 
itself and in several specimens of Paramcecium. A little dilute 
