430 



may be increased by artificial respiration, but never longer than for 

 a few minutes. Its principal action is conceived to be upon the 

 brain ; but it appears to act upon the heart also. The stomach some- 

 times bears marks of inflammation ; but the author has seen no in- 

 stance of the intestines being inflamed. 



The experiments of Mr. Brodie on corrosive sublimate, have led 

 him to conclusions very different from the preceding respecting its 

 mode of action. When applied to a wounded part, it produces a 

 slough, without any affection of the general system ; and when taken 

 internally, its effects, he thinks, may be best explained by its local 

 action on the stomach alone, unconnected with any absorption of it 

 into the circulation. 



When a solution of corrosive sublimate is taken into the stomach, 

 the mucous membrane is found of a dull grey colour, having lost its 

 texture, so as to be easily separated from the muscular coat ; and as 

 this precludes the idea of absorption into the circulation, Mr. Brodie 

 conceives that its deleterious effects depend entirely upon its che- 

 mical action on the stomach, and that the brain and heart are thence 

 affected by nervous sympathy. 



Observations of a second Comet, with Remarks on its Construction. By 

 William Herschel, LL.D. F.R.S. Read March 12, 1812. [Phil. 

 Trans. 1812, p. 229.] 



The tendency of Dr. Herschel's observations is to point out a dif- 

 ference between this second comet and the former, of which he lately 

 gave an account to the Society. 



The latter appeared to him as a nucleus about 5" in diameter, sur- 

 rounded by a very faint chevelure. Since this appearance on the 

 two first days of observation was not well defined, Dr. Herschel was 

 in doubt whether to consider the nucleus as corresponding to the 

 head of the former comet, or to the bright planetary body that he 

 had observed in its centre ; being extremely small in comparison to 

 the head, and as much too large to be supposed of a planetary con- 

 struction. But on two subsequent days of observation, the nucleus 

 was pretty well defined, even with a power of 170 ; and the author 

 was led to consider the latter as the more probable opinion. On the 

 fifth day of observation (which was the last time that it could be seen, 

 by reason of the interference of the moon's light), Dr. Herschel at- 

 tended carefully to the magnitudes of the body, as it appeared to 

 different magnifiers ; and by subsequent comparison on the following 

 morning of objects of known diameter with his recollection of these 

 magnitudes, he determined the measure of the nucleus to have been 

 5"'2744. 



Since the distance of this comet from us was at that time rather 

 greater than that of the sun, the real magnitude of the diameter thus 

 measured is estimated at 2637 miles. 



As the light of the chevelure was too feeble to be seen at this time, 

 on account of the light of the moon, its greatest extent, in a direc- 



