320 The Border-land of Chemistry and Biology. [ June, 
chemical elements. They were dissolved in water, and in- 
jected into a vein or artery in known quantities. The fatal 
doses for each individual were carefully noted, and a kymo- 
graph was connected with the femoral artery. The curves 
described by this instrument were strikingly characteristic 
for some of the isomorphous groups. 
Among the monatomic metals tried were lithium, sodium, 
rubidium, thallium, and silver. All agreed exactly in the 
mode of their physiological aCtion, but the fatal dose for 
rabbits, which was i grm. per kilo, of the weight of the 
animal for lithium sulphate, fell to o*o6 grm. for silver 
nitrate. In other words, lithium sulphate, to kill, must be 
introduced in the proportion of i part per thousand of the 
living weight, whilst of silver nitrate 6 parts per 100,000 
suffice. 
Among the group of the diatomic metals Dr. Blake expe- 
rimented with the salts of magnesium, iron, manganese, 
cobalt, nickel, copper, zinc, and cadmium. Here, again, 
the physiological aCtion is similar, the fatal dose being 
0*97 grm. per kilo, for magnesium sulphate, and only 
0*08 grm. per kilo, for cadmium sulphate. 
The salts of calcium, strontium, and barium agree also 
in their physiological aCtion, which is intensified from 
0*47 grm. per kilo, in calcium chloride to 0*043 grm. in 
barium chloride. The salts of this group produce contrac- 
tions of the voluntary muscles, even thirty to forty minutes 
after the aCtion of the heart has ceased. The reactions of 
lead salts resemble exactly those of the barium group, but 
at the same time they agree in some respeCts with those of 
the salts of silver. 
Among the tetratomic metals the author examined those 
of thorium, palladium, platinum, osmium, and gold. All 
have very intense physiological aCtion, ranging from 0*029 
grm. per kilo, in thorium sulphate to 0*003 grin. f° r gold 
chloride. The characteristic of this group is their effeCt on 
the aCtion of the heart. Salts of gold introduced into the 
blood, even in the minute proportion of 0*003 or 0*004 grm. 
per kilo., keep up the aCtion of the heart for several hours 
after death, though the body may have cooled down as far 
as 55 0 F. below its normal temperature. We may here ask if 
this is not the explanation of the aCtion of platinum 
chloride in prolonging the life of animals bitten by the 
cobra ? 
Among the hexatomic metals the salts of glucinum, 
aluminium, ancFiron (ferricum) were found to agree in their 
physiological aCtion, the death-dose being 0*023 grin. P^r 
