undergoes when in contact with Vegetables. 239 



vious experiments, was rather the effect of the growth of the 

 plant than the commencement of decomposition.* 



4ith Experiment. — A number of small mushrooms, having the 

 shape of little blue-bells, and congregated, of the species Agari- 

 cus digitalifbrmis, weighing together 60 grains, were placed 

 under a receiver inclosing 18.37 cubic feet of air, the thermo- 

 meter standing at 72°. At the end of nine hours its volume had 

 not sensibly changed. Analysis supplied the following results : 

 — The receiver enclosed, before the experiment, of nitrogen 

 14.53, of oxygen 3.84, -= 18.37; after the experiment, of nitro- 

 gen 14.43, of oxygen 1.14, of carbonic acid 2.80, = 18.37 



It is here to be observed, that the mushrooms employed in 

 this experiment are very short-lived, that they are of a very soft 

 consistence, and begin to deliquesce in a very short time. 



5th Experiment. — This experiment, which I regard as the 

 most conclusive of the series, was made upon the Boletus versi- 

 color. This species of mushroom usually grows upon decayed 

 trunks of trees, and old stumps of wood ; it is of a very tough 

 consistence, and, even when detached from the wood to which 

 it adheres, it exhibits no signs of decomposition for many days. 



Four individuals of this variety, weighing together 140 grains, 

 were detached from the trunk of an oak, in such a way that 

 along with each mushroom there was removed that portion of 

 the wood by which it was nourished. In this way these mush- 

 rooms could be subjected to experiment, without in the slight- 

 est degree altering their natural condition. They were intro- 

 duced under a receiver inclosing 35.00 cubic feet of air, the 

 thermometer being at 70° Fahr., and they were left exposed du- 

 ring the day-time for an interval of twelve hours. At the ex- 

 piration of this time, the volume of air in the receiver had in- 

 creased to 36.46 cubic feet. The result of the analysis was as 

 follows : — The receiver enclosed, before the experiment, of ni- 

 trogen 27.66, of oxygen 7.34, — 35.00 ; after the experiment, 

 of nitrogen 27.63, of oxygen .18, of carbonic acid 8.36, m 

 36.17. 



* In often repeating the above experiment I have remarked, that when 

 putrefaction had decidedly commenced in the mushroom employed, there was 

 generally a small quantity of hydrogen evolved. I have never, however, ob- 

 served this result when it was fresh. 



