British Association for the Advancement of Science. 29 
fusely in the blood, and united with the oxygen inspired ; hence 
they had carbonic acid. Dr. Carson had stated still further, that 
sighing improved the circulation. He had paid considerable at- 
tention to this, and he could not say that it improved it except in 
one way, and that was, it occasionally gave freer play to the lungs. 
They saw persons after being interested in any story almost sus- 
pend their breath, or, in other words, forget to breathe ; and as 
soon as the interest of the story terminated there was a very deep 
inspiration, which relieved the blood in the chest. But he was 
, that a series of inspirations did not invigorate the system, 
Dr. Conn had also stated that the blood was not facilitated in its 
return by inspiration. Experiments had frequently been perform- 
ed which proved this. 
Dust in the Lungs.—Dr. Macintosh read a communication 
from a medical student, on a disease of the lungs caused by the 
deposition of particles of dust. It would contribute, he observed, 
towards the elucidation of that class of diseases affecting artisans, 
which had, in a more systematic form, been treated by Mr. Thack- 
rah. In the neighborhood of Edinburgh were many stone-quar- 
ries, and the workers in which not unfrequently died from con- 
sumption. A mason, a worker in the Craigleith-quarry, was ill; 
he was bled and treated for a common cold, recovered, and re- 
turned to his work. A short time afterwards he was again taken 
ill, and, two years after the first attack, he died. During his ill- 
ness ecg ir afforded a dull sound ; on the right side the steth- 
pe indicated no respiratory murmur; on the left a paisiie 
vale. mag * death, the lungs presented a black ap ; 20 - 
oz. of fluid were found in the right side, and 4 oz. in the left ; 
there was no membrane, the pleura being fibrous, which was rare. 
Dr. Alison stated he ial only seen this state once, being on the 
_ pleura and cardiac portion of this kind of membrane ; both lungs 
were. completely studded with black tubercles, as ie they were 
, and cut like cartilage. Similar projections were on the 
pleura, id the bronchial glands were long and hard, grating when 
cut with the scalpel, owing toa cretaceous secretion like bone. 
The analysis of this cretaceous matter showed it to be principally 
the carbonate of lime. In the bronchial glands were carbonate 
of lime, silica, and alumina. He directed particular attention to 
this analysis, for Dr. William Gregory has published an account 
of the Craigleith-quarry stone, and the analysis of this stone gave 
