744 THE POPULAR SCIENCE MONTHLY. 



in the same yeast a sort of servant given by Nature to effect this diges- 

 tion. The servant is the unorganized inversive ferment. This ferment 

 is soluble, and, as it is not a plant, but an unorganized body destitute 

 of sensibility, it has not gone to sleep under the action of the ether, 

 and thus continues to fulfill its task." 



In the experiment already recorded on the germination of seeds 

 the interest is by no means confined to that which attaches itself to 

 the arrest of the organizing functions of the seed, those namely which 

 manifest themselves in the development of the radicle, and plumule, 

 and other organs of the young plant. Another phenomenon of great 

 significance becomes at the same time apparent : the anaesthetic exerts 

 no action on the concomitant chemical phenomena which in germinat- 

 ing seeds show themselves in the transformation of starch into sugar 

 under the influence of diastase (a soluble and non-living ferment which 

 also exists in the seed), and the absorption of oxygen with the exhala- 

 tion of carbonic acid. These go on as usual, the anaesthesiated seed 

 continuing to respire, as proved by the accumulation of carbonic acid 

 in the surrounding air. The presence of the carbonic acid was ren- 

 dered evident by placing in the same vessel with the seeds which were 

 the object of the experiment a solution of barytes, when the carbonate 

 became precipitated from the solution in quantity equal to that pro- 

 duced in a similar experiment with seeds germinating in unetherized 

 air. 



So, also, in the experiment which proves that the faculty possessed 

 by the chlorophyllian cells of absorbing carbonic acid and exhaling 

 oxygen under the influence of light may be arrested by anaesthetics, it 

 could be seen that the plant, while in a state of anaesthesia, continued 

 to respire in the manner of animals ; that is, it continued to absorb 

 oxygen and exhale cai'bonic acid. This is the true respiratory func- 

 tion which was previously masked by the predominant function of as- 

 similation, which devolves on the green cells of plants, and which 

 manifests itself under the influence of light in the absorption of car- 

 bonic acid and the exhalation of oxygen. 



It must not, however, be supposed that the respiration of plants is 

 entirely independent of life. The conditions which bring the oxygen 

 of the air and the combustible matter of the respiring plant into such 

 relations as may allow them to act on one another are still under its 

 control, and we must conclude that in Claude Bernard's experiment 

 the anaesthesia had not been carried so far as to arrest such j>roperties 

 of the living tissues as are needed for this. 



The quite recent researches of Schutzenberger, who has investi- 

 gated the process of respiration as it takes place in the cell of the 

 yeast-fungus, have shown that vitality is a factor in this process. He 

 has shown that fresh yeast, placed in water, breathes like an aquatic 

 animal, disengaging carbonic acid, and causing the oxygen contained 

 in the water to disappear. That this phenomenon is a function of the 



