TRANSACTIONS OF THE SECTIONS. 101 



Notice of an extraordinary case of Spina bifida. By Mr. Evans. 



The patient was a boy of twelve years of age, enjoying excellent ge- 

 neral health in other respects ; he was strong and active, but his head 

 seemed enlarged from chronic hydrocephalus. The tumour occupied 

 the lumbar regions, was semi-transparent, and the size of a child's head. 



Observations on Poisoning by the Vapours of burning Charcoal. 

 By GoLDiNG Bird, M.D. 



Dr. Bird stated, that he was induced to state the result of some ex- 

 perimental investigations on this subject, from the discordant opinions 

 hitherto published on the various questions connected with it in a toxi- 

 cological point of view. An opinion has been held, that vapours of 

 carbonic acid were more injurious when produced by the combustion 

 of coal and charcoal, than from any other source, on account of the ad- 

 mixture of light carburetted hydrogen gas. This opinion he dissented 

 from, as it was well known that in coal-mines the fire-damp, as this gas 

 was called, was inhaled with perfect impunity. To ascertain the modus 

 agendi of the gas when inhaled, he made numerous experiments, by im- 

 mersing animals in different mixtures of it and atmospheric air, as well 

 as in the pure gas. In the latter case, the animals died asphyxiated, as 

 when immersed in water or mercury, the spasm of the glottis prevent- 

 ing any portion of it from being inhaled. If not more than twenty-five 

 per cent, be present, then respiration will go on, and its true poisonous 

 effects takes place. As to the amount of this gas necessary to produce 

 fatal effects. Dr. Bird found that, as a general rule, any quantity above 

 3^ per cent, was capable of producing death. Two opinions prevailed 

 on the nature of these properties : the first was, that the gas acted ne- 

 gatively, as pure nitrogen or hydrogen is knoAvn to do, by preventing 

 the due supply of oxygen. To test this opinion, he formed a mixture 

 containing twenty-one parts of oxygen, and seventy-nine of carbonic 

 acid, and death followed instantly from immersion in it ; and the same 

 result followed when the proportions were reversed, although a taper 

 burned brilliantly in the latter combination ; showing, that the burning 

 of a light in any suspected situation is not always a safe test of the ab- 

 sence of danger. The second opinion is, that this gas, when respired, 

 exerts a specific poisonous action on the nervous system. This latter, 

 Dr. Bird adopts, from various considerations drawn from his direct ex- 

 periments, and from the symptoms observed in numerous cases. These 

 are principally those denominated cerebral, such as head-ache, vertigo, 

 suffused eyes, mental horror to an intense degree. Even with these 

 symptoms, respiration may go on freely. Death is frequently preceded 

 by vomiting, which is a marked symptom of cerebral disease. In cases 

 where recovery has taken place, the sequelae are decidedly of nervous 

 character : they have been, partial paralysis, dumbness, and idiocy ; 

 and this poisonous effect he thought took place independently of ab- 

 sorption, from its immediate effects on the nervous system, to which it 

 was applied. Death has also been induced by its external spplication 



