NICKEL-COBALT. 
§ 908.] 
709 
may be classed as poisonous. The experiments of Gmelin had, prior to 
Stuart’s researches, shown that nickel sulphate introduced into the 
stomach acted as an irritant poison, and, if introduced into the blood, 
caused death by cardiac paralysis. Anderson Stuart, desiring to avoid 
all local irritant action, dissolved nickel carbonate in acid citrate of soda 
by the aid of a gentle heat ; he then evaporated the solution, and 
obtained a glass which, if too alkaline, was neutralised by citric acid, 
until its reaction approximated to the feeble alkalinity of the blood ; the 
cobalt salt was produced in the same way. The animals experimented 
on were frogs, fish, pigeons, rats, guinea-pigs, rabbits, cats, and dogs—- 
in all 200. The lethal dose of nickelous oxide, when subcutaneously 
injected in the soluble compound described, was found to be as follows :— 
frogs, *08 grm. per kilogramme ; pigeons, -06 ; guinea-pigs, -03 ; rats, 
•025 ; cats, -01 ; rabbits, -009 ; and dogs, -007. The cobaltous oxide 
was found to be much less active, requiring the above doses to be in¬ 
creased about two-thirds. In other respects, its physiological action 
seems to be very similar to that of nickelous oxide. 
§ 908. Symptoms.—Frogs. —A large dose injected into the dorsal 
lymph sac of the frog causes the following symptoms :—The colour of 
the skin all over the body becomes darker and more uniform, and not 
infrequently a white froth is abundantly poured over the integument. 
After an interval of about twenty minutes the frog sits quietly, the eyes 
retracted and shut ; if molested, it moves clumsily. When quiet, the 
fore limbs are weak, and the hind legs drawn up very peculiarly, the 
thighs being jammed up so against the body that they come to lie on 
the dorsal aspect of the sides of the frog, and the legs are so much flexed 
that the feet lie on the animal’s back, quite internal to the plane of 
the thighs. Soon fibrillary twitchings are observed in the muscles of the 
abdominal wall, then feeble twitchings of the fingers, and muscles of the 
fore limbs generally ; lastly, the toes are seen to twitch, and then the 
muscles of the hind limbs—this order is nearly always observed ; now 
spasmodic gaping and incoordinate movements are seen, and the general 
aspect is not unlike the symptoms caused by picrotoxin. After this, 
tetanus sets in, and the symptoms then resemble those of strychnine ; the 
next stage is stupefaction and voluntary motor paresis ; the respiratory 
movements become feeble, and the paresis passes into paralysis. The 
heart beats more and more slowly and feebly, and death gradually and 
imperceptibly supervenes. The post-mortem appearances are well marked 
— i.e. rigor mortis, slight congestion of the alimentary tract, the heart 
with the auricle much dilated and filled with dark blood, the ventricle 
mostly small, pale, and semi-contracted. For some time after death, the 
nerve trunks and muscles react to the induction current. 
Pigeons. —In experiments on pigeons the symptoms were those of dul- 
ness and stupor, jerkings of different sets of muscles, and then death quietly. 
