824 
REPORTS OF MEETINGS. 
irritation in the nerve centres, and in bodies of high molecular 
weight, to cause spasms. 4. Nitrogen shows great versatility 
in the part it plays. Many bodies containing it, such as the 
natural alkaloids, have their poisonous action greatly lessened by 
addition of methyl and similar radicals; while others become 
much more active by such addition. 5. Increase of molecular 
weight corresponds with increased toxical action. 6. Polymeric 
bodies have a deficient, and in some cases, a much more 
energetic effect on the organism than the simple compounds 
from which they are built up. Professor Ramsay concluded by 
pointing out the importance of such investigations, as tending to 
throw light on the action of drugs on the animal economy, and 
as leading the way to the discovery of new ones. 
At the meeting in March, Mr. F. F. Tuckett and Dr. 
Beddoe made a communication regarding “ The Evidence as to 
the recent gradual Diminution in the Dimensions of the Human 
Head in this Country,” which appears in the foregoing pages. 
At the April meeting, Mr. C. Richardson, C.E., read a paper 
on “The Age of the Wye,” also fully reported in the present Part. 
When the Society met again, in October, Professor Sollas 
read a paper on “ The Connection between Volcanoes and 
Mineral Veins.” He began by alluding to the misconception 
which existed regarding the nature of mineral veins, the pre- 
vailing idea being that they resembled the veins of the human 
body. A mineral vein is a great fissure in the earth’s crust, 
lined with quartz, in which we find various metallic compounds 
deposited, such as sulphide of copper, &c. Large fissures are 
produced by what are known as “lines of fault,” which are 
cracks in the earth’s crust accompanied by dislocation in the 
adjacent portions. In Cornwall we find numerous examples of 
faults which are lined with quartz. This substance is extremely 
insoluble, but in order to account for its presence in these veins, 
it must at some period have been held in solution. A thin slice 
