164 THE AMERICAN MONTHLY. [September, 



understand aright the tendency of modern research concerning this matter, 

 the number of forms which cannot be assigned with good reason to either the 

 vegetable or tiie animal series is constantly growing smaller. In short, it 

 seems to me Protista is gradually tapering to a point as knowledge advances, 

 and at no very distant period there will be no use for it in the sense it was 

 first proposed and limited. 



I prefer to keep to the old lines and regard these lowest beings as either 

 plants or animals according to the best light we have. That mistakes will 

 be made for subsequent study to correct must be expected. But that there 

 will be more than by any yet proposed arrangement I cannot believe. 



This little swimmer from the infusion of ha}^ is known in the system as He- 

 teromita. Why is Heteromita an animal.'' i. It feeds on organic matter of 

 the infusion in which it flourishes. Since it contains in its body none of that 

 peculiar substance, chlorophyl, which enables protoplasm to create its own 

 food out of the simple substances, H^O, COo, and NH3, in the pi"esence of 

 sun-light. On the other hand it must borrow its substance and energy from 

 other and independent sources. 



At this point two questions naturally arise which are in the nature of ex- 

 ceptions : — (i) There are well known and undisputed plants with the habit 

 of animals, i. e.^ they feed on organic food prepared outside themselves, 

 whilst it is the rule that animals feed, as our infusorian does, upon substance 

 prepared ultimately by plants, and that the plant prepares its own ; the Fungi 

 and certain colorless flowering plants reverse the rule and are exceptions. 

 That they have acquired this animal habit will not be difticult to believe if 

 we take into account the prevalence of parasitism and the wonderful changes 

 and modifications of form and habits which it implies. The Fungi are plants, 

 as their life-histories, development, and structure attest. Besides, they may 

 feed on such chemicals as acetates, tartrates, and ammonia ; this animals can- 

 not do. (2) The second exception is this : — certain undoubted animals, e.^'., 

 the green Hydra, some fresh-water sponges, and infusoria, are perverted b}' 

 chlorophyl-bearing bodies. These are said to possess the power, therefore, 

 of creating their own food in manner similar to the ordinary plant. It should 

 be noted that if it proves to be true that these green animals have acquired 

 the characteristic habit of the vegetable, another fact is added tending to prove 

 that protoplasm of either kingdom is capable of great accommodation or 

 change of habits. 



In regard to the question of the possibility of carrying one's vegetable gar- 

 den in one's stomach I w*ish to express a doubt. I cannot see that the species 

 whose tissues are filled with these bodies, and on which, or on their products, 

 it is supposed to feed, possesses an adequate advantage over those not thus 

 supplied. Our green Hydra is not so abundant as the brown one, nor will ' 

 hold out longer under unfavorable conditions ; it feeds as voraciously. Tv, 

 masses of fresh-water sponge are often seen growing side by side, one b,, 

 liant green, the other colorless, or one mass may be partly green and pr, •' 

 colorless. I am unable to see that the green example or the green pa ", 



any advantage over the colorless associate. A particular infusorian Hoi 'K •' 

 . .... . nclance 



(which I shall refer to atanother time during^ this meeting) occurs in abt. , 



•^ . mioarts 



in a certain slusfsfish stream near Buffalo. It is a deep green and often , ^ 



its hue to the water and submerged objects in "which it accumulates. ^ ,. 



ber of these were recently taken and subjected to a series of varyi, *V, , 



tions, whilst check experiments were conducted with the uncolore^ . - , 



... . e an" anci 



leodon farctus. Under varied conditions as to light, temperatu ' ', 



absence of food, so far as I could determine, the green species j r -1 



advantage as to enduring qualities over the other. The usefu' , y . ,. 



chlorophyl-bodies, if the}' are useful, is not, it seems to me, ir 



of nutrition or respiration. 



