SCIENTIFIC SUMMARY. 
437 
samples were found to contain oxide of zinc. The white powders for the 
skin were found to he chiefly made up of carbonate of lime and magnesia, 
clay, and French chalk, and as far, therefore, as these materials are con- 
cerned, are harmless, except in so far as their application may interfere with 
the healthy action of the skin. — American Journal of Pharmacy, July 1. 
Physiological Effects of Carbonic Acid. — A valuable paper on this subject 
was read by Dr. B. W. Richardson, F.R.S., at the British Association meet- 
ing at Liverpool. The author first demonstrated from a specimen the result 
of subjecting a vegetable alkaline infusion to the action of carbonic acid 
under pressure. The result was a thick fluid substance, which resembled 
the fluid which exudes as germs from some trees. When this fluid was 
gently dried, it became a semi-solid substance, which yielded elastic fibres, 
and somewhat resembled conachone. (?) This observation had led the author 
to study the effect of carbonic acid on albumen, serum of blood, blood itself, 
bronchial secretion, and other organic fluids. When the serum of blood was 
thus treated, with carbonic acid under pressure and gentle warmth (96° F.), 
the colloidal part was separated ; but when the blood, with the fibrine re- 
moved from it, was treated, there was no direct separation, the blood 
corpuscles seeming for a time to engage the gas by condensation of it. But 
blood containing fibrine, and held fluid by tribasic phosphate of soda, was 
at once coagulated by the acid. The bronchial secretion is thickened by 
carbonic acid, and a tenacious fluid is obtained, resembling the secretion 
which occurs in asthma and bronchitis, while secretions on serous surfaces 
are thickened and rendered adhesive. After detail of many other facts, Dr. 
Richardson concluded by showing what bearing this subject had of a 
practical kind. In the first place, the research had relation to the question 
of elasticity of organic substances ; and secondly, on the direct action of 
carbonic acid on the production of vegetable juices. But the greatest interest 
concentrated on the relation of the research to some of the diseases of the 
animal body. Thus, in instances where the temperature of the body is 
raised and the production of carbonic acid is excessive, the blood on the 
right side of the heart has its fibrine often precipitated, and in many other 
cases fibrinous or albuminous exuded fluids are solidified, as is the case in 
croup. The author, in the course of his paper, explained how rapidly blood 
charged with carbonic acid absorbed oxygen when exposed to that gas, and 
he held that carbonic acid in the venous blood was as essential to the process 
of respiration as was the oxygen in the pulmonary organs. 
Methyl Compounds.— Among the many researches made during the year, 
and reported on to the British Association, Dr. Richardson said, among 
other things that had been discovered by the experiments made with 
ansesthetical bodies was, that it was possible to remove pain without remov- 
ing consciousness, although any act performed by the patient was afterwards 
forgotten. The nervous centre which produced sensibility was affected 
and paralysed before those centres which were devoted to consciousness, 
lie thought it very possible they would be able to discover an agency which 
would produce paralysis of sensation through the body without destroying 
consciousness at all. 
Are the two Sides of the Brain alike ? — Dr. Brown- Sequard thinks not. 
In the course of his remarks, at the British Association at Liverpool, he 
