WHAT IS A PLANT? 157 



seeds — such as peas, or some budding floiuers — such as chamomile 

 flowers, or, as a third case, some Fungi — such as mushrooms (the 

 order possessing no chlorophyll) ; place them in a tightly-stop- 

 pered bottle ; after a few hours introduce a lighted taper into the 

 bottle ; it will be extinguished at once. Or lead the gas evolved by 

 the bodies named into a solution of lime-water ; calcic-carbonate 

 is quickly formed. From all these experiments we gather that 

 green parts of plants in darkness, and parts not green, and Fungi, 

 in either sunshine or darkness, evolve not oxygen, but carbonic 

 acid, precisely as animals do. They possess, that is, the fimction of 

 respiration. Familiar examples may any day be seen in the 

 evolution of this acid in the process of malting, which is really 

 one of corn sprouting by artificial means ; also, in carbonic acid 

 coming off from yeast, which is really a case of its evolution 

 from a Fungus. Thus we see that on the ground of respiration 

 we cannot build up any distinctive diagnosis of animal-life as 

 opposed to plant-life. As Huxley says, " The difference vanishes 

 with the sunshine," even with the green parts of plants, while with 

 parts not green and the Fungi, no difference exists at any time. 

 We must, therefore, resign the distinction, or write down the oak 

 as a plant by day, an animal by night, a statement manifestly 

 absurd. Moreover, modern research, especially Bernard's 

 experiments, show that the green parts of plants, even in sunshine, 

 do truly respire, or evolve carbonic acid to some extent, only its 

 effects are hidden by the excess of the more marked process of 

 their evolution of oxygen. Still one further remark. It has been 

 shown with positive proof, by Mr. P. Geddes, that some animals 

 possessing chlorophyll, such as Spongilla, Hydra, and Convoluta, 

 (all before-named,) and others on which iVlgse are parasitic (in 

 the sense of living in their substance), such as the Radiolaria, 

 A?ifhea cerciis, var. smaragdina, and Helianthus, two well-known 

 anemones, do actually evolve oxygen, exactly like chlorophyllian 

 plants ! So that, on both the animal and the plant sides, our 

 diagnosis fails us. Therefore, we see that all the four distinctions 

 of Cuvier fail to be absolute and diagnostic in the light and under 

 the test of recent biological discovery. 



X. — Function of Sensation. The possession of the power 

 to " feel " was long held to be peculiar to animals, and a distinction 



