1883-84-] Edinburgh Naturalists' Field Club. 173 



The points of distinction — to all of which there are fouiid excc^t- 

 tions of more or loss importance — that are generally stated arc as 

 follows : — 



(1) Animals are endowed with loccnnotice power. This same 

 power, hoAvever, is found in the case of the reproductive cells of 

 many of oi;r lower plants, such as Ulva, Pandorina, &c., these 

 cells existing as zoospores or zoogonidia, which are provided with 

 actively motile cilia, enabling them readily and rapidly to change 

 their place ; and the male reproductive cells or antheridia of even 

 higher Vascular Cryptogams, such as Ferns and Horsetails, are 

 similarly provided Avith locomotive organs. 



(2) Animals possess irritability. This is also exhibited by 

 plants, such as the well-known Sensitive Plant [Mimosa semitiva), 

 the leaves of which suddenly droop if subjected to mechanical, 

 chemical, or electrical stimuli, — vapour of chloroform, for example, 

 l)roducing drooping of longer continuance than a similar effect 

 brought about by mere mechanical irritation. The stamens, too, of 

 the Barberry are sensitive to mechanical stimulation. They are 

 jointed to the receptacle, and, when touched, move inwards towards 

 the centre of the flower. A reverse movement takes place in the 

 case of the stamens of Eock Rose [FleJiantltemum), when similarly 

 affected : these, in the normal, unstimulated condition, are erect, but 

 by gently squeezing the outside of the flower, a movement away 

 from the pistil occurs. 



(3) Plants possess cellulose in the walls of their constituent cells. 

 This substance is chemically air isomer of starch (C-qH^qO^), and, 

 although not occurring widely in the Animal Kingdom, it seems 

 identical with the " tunicin " found in the tests of Ascidians ; while 

 the amyloid and saccharine matters which are so conspicuous vege- 

 table products are also " of very wide, if not universal, occurrence in 

 animals " (Hux.), being represented by the glycogen of the liver. 

 It is, however, a well-known fact that the combustion odour of 

 feathers, or other animal products, is markedly different from the 

 odour given off by burning wood, and here avo have a general dis- 

 tinction of importance between the two kingdoms. 



(4) In plants generally there is a preponderance of the ternary 

 compounds of carbon, although of vegetable protoplasm nitrogen is 

 also an important constituent, nitrogenous food being necessary for 

 the full complement of seed in such insectivorous plants as Pin- 

 guicula, IS'epenthes, and others. Animals, on the other hand, 

 abound in quaternary or quinary carbon unions — the albumen, so Avell 

 seen in the Avhite of egg, possessing a constitution indicated, accord- 

 ing to some, by the formula C^^^H^^QiSr^gO^oS^ ; while hainnoglobin, 

 or the red colouring matter of blood, is perhaps one of the most 

 complex of all organic bodies, being represented, according to Preyer, 

 by the formula CcooHoeoNis^FeSgO,;^ ; the fact that iron (Fe) is 



