BIOLOGY. 287 



this took so deep a hold on him that it was impossible to shake 

 it off. 



Other trials he has made with it convince him that it has more 

 power than that brought from India, on one occasion four times 

 the dose of the latter failing to produce the effect of the Kentucky 

 specimen. 



He has his extract made from a tincture, removing "certain in- 

 ert matters by an akali ; he intimates the hope that in the present 

 revision of the U. S. Pharmacopoeia the ex. cannibis purifactum 

 may be replaced by a preparation to be called Resena cannibis, 

 and to be made by precipitating the concentrated tincture by 

 water rendered strongly alkaline by soda or potash. 



The native plant, if used, will always be more reliable than the 

 imported, from the certainty of freshness, whilst the cost of it is 

 hardly anything. 



PHYSIOLOGICAL EFFECTS OF CARBONIC ACID. 



At the meeting of the British Association a paper was read by 

 Dr. B. W. Richardson, entitled " New Physiological Researches 

 on the Effects of Carbonic Acid." In the course of an interesting 

 communication he explained that the observations he had made 

 were new, in that they related to the direct action of carbonic 

 acid on animal and vegetable fluids, and they were interesting 

 equally to the zoologist and botanist as to the anatomist. 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 resem- 

 bled the fluid which exudes as gums 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 secre- 

 tion, and other organic fluids. When the serum of blood 

 was thus treated with the carbonic acid under pressure and 

 gentle warmth, 26 F., the colloidal part was separated; but 

 when the blood, with the fibrine removed 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 holding fluid by tribasic phosphate of 

 soda, was at once coagulated by the acid. The bronchial secre- 

 tion was thickened by carbonic acid, and a tenacious fluid was ob- 

 tained, resembling the secretion which occurred in asthma and 

 bronchitis, while secretions on serous surfaces were thickened 

 and rendered adhesive. After detailing 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 vege- 

 table juices. But the greatest interest concentrated on the rela- 

 tion of the research to some of the diseases of the animal body. 



