311 



main and tlie greenhouse is not stated, but it appears tb at trees grow- 

 ing between the former and the latter were completely killed. It was 

 to determine whether the result in dispute could be effected by the 

 action of the gas. The plants were growing in pots placed upon 

 stands, and it was therefore impossible that they should be injured 

 through the medium of their roots. It was then to determine what 

 might be the influence of the gas in question upon the aerial portions of 

 plants that the investigation about to be described was instituted. In 

 order to secure such conditions that the plants might be confined in 

 an atmosphere containing a given quantity of gas, and yet be provided 

 with the requisite degree of light, heat, and moisture, the plants were 

 placed in closed boxes, provided with glass sides, and the joints of 

 Nvhich were cemented with white lead. When all was secured a tube 

 of glass was introduced through the side of the box and connected with 

 the stop-cock of a gasometer. The stop-cock of the gasometer was then 

 opened, and the gas allowed to flow into the box, until the entire con- 

 tents of the former were transferred to the latter. The whole was then 

 allowed to stand until the following day, when the gasometer was again 

 filled with gas taken from the pipes supplying the laboratory, and one- 

 half the contents transferred to the box. On the next day press of 

 other duties called m.y attention away from this work entirely, and the 

 box therefore received no gas. On the fourth day, however, one-half 

 the contents of the gasometer were introduced, and another day al- 

 lowed to intervene before another ai)plication. Gas was then intro- 

 duced into the box on four occasions, so that the amounts transferred, 

 allowing ten gallons for the capacity of the gasometer, were, 24th, 

 about 10 gallons ; 2oth, about 5 gallons ; 27th, about 5 gallons ; March 

 1, about 5 gallons. During this time an occasional leaf, as well as one 

 of the buds, fell from the plaut, and on March 2, on opening the box 

 to apply water to the plant, a slight jar caused a number of tlie leaves 

 to fall. The plaut was then carefully removed from the box, when, 

 a sharp shock caused nearly. all the leaves to fall. The leaves which 

 had fallen were then gathered about the base of the plant, the whole 

 placed in a convenient position, and, together with the other plant, 

 which had been submitted to the same conditions excepting the treat- 

 ment with gas, and which remained perfectly sound and healthy, was 

 photographed. From the photograph thus obtained the accompany- 

 ing illustration was made. Now, what was the relative amount 

 employed ? .The dimensions of the box were, horizontal cross-sec- 

 tion, two feet square; height, four feet. Calculating from the data 

 at hand, we find that the amount first introduced was equivalent to 

 about 7.7 per cent, of the entire volume of the box, and that the quan- 

 tity subsequently introduced, being one-half this amount, was but 

 3.35 per cent. Without making any allowances for escape of the gas 

 by diffusion, which .probably took place, reasoning from the fact that 

 when the box was opened no odor of gas was perceptible within the 

 box, we find that after the first day the amount of gas did not exceed 

 4 per cent, of the volume of the box. It is however probable that the 

 average quantity was much less than 3 per cent., and I am inclined to 

 the oi)inion that if camelias or other plants be confined in an atmos- 

 phere containing continually 1 to 2 per cent, of illuminating gas, they 

 must suffer, and ultimately be killed. 



Liberation of caebonic acid by respiration and perspira- 

 tion OF various animals under different conditions. — This sub- 

 ject has lately been very thoroughly studied by Dr. Eud. Pott, of Jena, 



