IX. — The Relative Absorption of Nickel and Cobalt, By 

 R. H. Chittenden and Charles Norris, Jr., Ph.B. 



When nickel and cobalt were first discovered they were supposed 

 to be possessed of decided toxic properties, and nickel particularly 

 was looked on as more poisonous than copper. Examination, how- 

 ever, of many of the supposed cases of nickel poisoning led to the 

 view that toxic action was due, mainly at least, to the presence of 

 arsenical impurities, with which German nickel particularly was 

 known to be contaminated. Gradually, therefore, the view has be- 

 come widespread that nickel and cobalt are no more poisonous than 

 iron, with which chemically they are so closely related. We have 

 not, however, been able to find many very definite statements re- 

 garding their physiological or toxic action. Blake * in his study of 

 the relation between isomorphism, molecular weight, and physiolog- 

 ical action, places the sulphates of nickel and cobalt in the same 

 group with copper, zinc, iron, etc., and further arranges cobalt, cop- 

 per and zinc together in a sub-group, on account of their arresting 

 the action of the heart and preventing the coagulation of the blood. 

 Nickel, liowever, is placed with manganese on account of its exert- 

 ing a marked influence on the nervous system. As to the intensity 

 of their physiological action, Blake apparently considers nickel and 

 copper of the same strength, while cobalt is figured as one-twentieth 

 stronger. Both salts, liowever, kill by arresting the action of the 

 heart and in lethal action cobalt stands first.f Woodman and Tidy J 

 state that 30 grains of the oxide of cobalt given to a dog proved 

 fatal in a few hours, whilst 3 grains of the sulphate injected into a 

 vein proved fatal in four days. With nickel, the same writers state 

 that vomiting is freely induced in a dog by a dose of 20 grains of 

 the sulphate, whilst 10 grains injected into the jugular vein will de- 

 stroy life instantly. Finally, Brunton and Cash have found that 

 nickel and cobalt, like most other metallic salts, cause slight contrac- 

 tion of the blood vessels. § 



* American Jouraal of Science and Arts, vol. vii, p. 194. 

 f See Brunton's Pharmacology and Therapeutics, p. 51. 

 X Forensic Medicine and Toxicology, p. 171 and p. 214. 

 gBruDton's Pharmacology, p. 246. 



