44 POISONS : THEIR EFFECTS AND DETECTION. [§ 33 . 
If the red blood corpuscles dissolve, it shows the substance has a 
haemolytic poisonous action on the red blood corpuscles. 
Examples of poisons which dissolve the red blood corpuscles are— 
arseniuretted hydrogen, the poison of the bee, snake poison generally, 
saponin, phallin. 
2. Action on Infusoria. —The infusoria are extremely sensitive to 
the poisonous alkaloids and other chemical agents. Strong doses of the 
alkaloids cause a contraction of the cell contents, and somewhat rapid 
disintegration of the whole body ; moderate doses at first quicken the 
movements, then the body gets perceptibly larger, and finally, as in the 
first case, there is disintegration of the animal substance. 
The most suitable for the research are the larger kinds, such as 
paramaecia : these are easily obtained by steeping hay in water and 
incubating at blood heat for about 24 hours. Among a number of species 
will be observed several paramaecia, such as Paramceciwn caudatum and 
others. Still more suitable organisms are, however, the opalinae. 
O'palina ranarum. —The opalinae are ciliated organisms which are 
found in the rectum of almost every frog at all times of the year. 
They are oval, can just be seen with unaided sight as white points, con¬ 
tain a number of clear nuclei, and are capable of active movement by 
reason of the numbers of cilia which clothe the surface. 
They are usually obtained from the frog by first paralysing the 
brain so as to destroy sensibility to pain, cutting out the intestine and 
the lower part of the caecum, and slitting it up while immersed in a 0*6 
per cent, solution of common salt. 
The inner lining may now be stroked by means of a camel’s-hair 
brush and the opalinae thus detached. Two drops of water containing 
opalinae substances are added in aqueous solution of known but varying 
strength, and the behaviour of the organisms observed as compared with 
one or more “ controls ” contained in watch-glasses or shallow dishes. A 
weak magnifying power is alone required. The chief changes are either 
swelling or shrinking, alterations in form, and often the appearance of 
several vacuoles ; sometimes, again, the contents become granular. 
Kossbach 1 gives the following intimations of the proportion of the 
toxic principle necessary to cause death :—Strychnine 1 part dissolved 
in 1500 of water ; veratrine 1 in 8000 ; quinine 1 in 5000 ; atropine 1 
in 1000 ; the mineral acids 1 in 400-600 ; salts 1 in 200-300. 
3. Cephalopoda. —The action of a few poisons on the cephalopoda 
has been investigated by M. E. Yung. 2 Curara placed on the skin had 
no effect, but on the branchiae led to general paralysis. If given in even 
fifteen times a greater dose than necessary to kill a rabbit, it was not 
always fatal. Strychnine, dissolved in sea-water, in the proportion of 
1 N. J. Rossbach, Pharm. Zeitschr. fur Russland, xix. 628. 
2 Compt. Rend., xci. 306. 
