336 On the Quantity of Carbonic Acid Gas [NoV. 



the quantity much more than any thing else that lias been made 

 the subject of experiment. This was so unexpected on my part 

 that I was prepared to meet with the reverse. I was first led, 

 however, to suspect the accuracy of my opinion by observing 

 that when 1 took porter with my dinner die quantity was always 

 much reduced below the standard, when the reverse was the case 

 when I only took water. This induced me to make some expe- 

 riments on the subject; and their results were such as fully to 

 persuade me that alcohol, in every state, and in every quantity, 

 uniformly lessens, in a greater or less degree, the quantity of 

 carbonic acid gas elicited, according to the quantity and circum- 

 stances under which it is taken. When taken upon an empty 

 stomach its effects are most remarkable : in this case they appear 

 to take place, and the depression to be greatest, almost instanta- 

 neously : after a short time, however, the powers of the consti- 

 tution appear to rally, and the quantity rapidly increases ; then 

 it sinks again, and afterwards slowly rises to the standard.* 

 Upon a full stomach, as after dinner, the effects of vinous 

 liquors are more slow, but no less sure and remarkable ; I have 

 even thought them more permanent ; but this might arise from 

 my having taken a larger quantity than I chose to do upon an 

 empty stomach. As long as their effects are perceptible, so long 

 is the quantity of carbonic acid gas emitted below the standard. 

 With me these effects go off with frequent yawnings, and with 

 asensation as if I had just awaken from sleep. Under these 

 circumstances 1 hav» found the quantity generally much above 

 the standard ; and hence it would seem that the system is then 

 freeing itself of the retained carbon. Very similar to the effects 

 of alcohol are those of tea when strong. I had suspected this 

 from what I had noticed after breakfast ; and with the view of 

 ascertaining the fact, prepared a strong infusion, three or four 

 ounces of which I took cold when the quantity was at its maxi- 

 mum : the result was a very considerable diminution, as will be 

 seen by recurring to the experiment. This will probably account 

 for its exhilarating and other effects.t See Exper. 8, 9, 10, 1 1, 

 and 12. 



Sleep.— Of course I have not had it in my power to ascertain 

 the quantity of carbonic acid given off during sleep. I am, 

 however, decidedly of the opinion of Messrs. Allan and Pepys, 



* I have generally observed this sort of oieiltalion when the quantity ha» 

 been suddenly and greatly raised or depressed from anv cause, and I have 

 been ready to account for it by supposing that the sudden and great exertions 

 of the animal powers required to counteract the effects of a poison, or other 

 injurious cau»e operating, m^de them, as it were, overact themselves. 



t I have not tried opium, but have no doubt that its eftecs are precisely 

 similar to those of alcohol. I hope soon, however, to investigate the ellects 

 not only of this, but of some other articles of the materia niedica and alim>" 

 taiia. 



