298 PROGRESS OF MICROSCOPICAL SCIENCE. 
is injected into a man, it t!:en follows, since the solid residue contains 
10 per cent. of cobric acid, that one-fifth of a grain would be fatal, so 
that we have here a rival to aconitia weight for weight in its power 
of destruction.” 
t 
\i | 
Cobric Acid magnified 250 diameters. 
The Blood-vessels of Muscle under the Microscope.—Mr. W. H. 
Gaskell has recently presented a paper on this subject to the Royal 
Society, in which he describes the results of observations made on the 
living blood-vessels of the mylohyoid of the frog. He says he found 
that the mylohyoid muscle was the most suitable one for his purpose, 
it being easy to prepare it for microscopic observation without da- 
maging the circulation through it, and, in fact, without even touching 
the muscle; whilst, owing to its thinness, the small amount of con- 
nective tissue in the neighbourhood of the vessels, and the absence of 
pigment-cells, it is possible here to measure with a micrometer eye- 
