44 



deny the entity oiheat^ to account for the alternate exhibition 

 and extinction of the thermometric heat, that is, in fact, 

 evolved and absorbed by those mutations of water. 



The Author again referring to the long standing con- 

 trovercies concerning the essential nature of heat, stated that 

 more than one hundred works have been published on the 

 subject during the last 200 years, and yet no conclusion has 

 been arrived at, as to the soundness of either of the original 

 theories above cited, nor have any discoveries been made that 

 explain the agency of heat, in the mutations of water, since 

 the days of Bacon and Boyle, with the sole exception of 

 those of Dr. Black, which appear to prove its latent state in 

 bodies. And since we have no settled doctrine as to its 

 essence, we must allow that the subject is of philosophical 

 interest, and especially this branch of it concerning latent 

 heat, in defence of which these notes are offered. 



The President said that some very interesting experi- 

 ments made by Mr. Dyer, many years ago, were in favor of 

 the dynamical theory of heat, which he believed to be fully 

 able to explain the phenomena ascribed by Black to " latent 

 heat." 



A Paper was read by Dr. R. Angus Smith, " On the 

 Production and Prevention of Malaria." 



The Author did not pretend to enter on the whole subject, 

 but to give a few observations which he considered fitted for 

 its illustration — Malaria has unquestionably been proved to 

 be caused by the decomposition of organised bodies. If so, 

 it must exist to some extent everywhere. By the mode of 

 testing the air invented by the Author, every place tried at 

 home and abroad was found to have some oxidizable matter 

 in it, although in some this was extremely small. In such 

 cases the matter was probably oxidized to a state in which 

 it would be innocuous. This oxidizable matter no doubt 

 rises, in a great measure, from vegetation. Vegetation does 

 not merely grow ; it dies. This death may be caused by 



