820 REPORT— 1901. 



phytomeric hypotheses. We now realise that in an Angiospermthe living plurinu- 

 cleated protoplasm is spread over a skeletal support furnished by the cell-chambers 

 of shoot and root. The energid of each living cell is connected with the adjacent 

 energids by the protoplasmic threads piercing the separating cell-membrane. The 

 protoplasm thus forms a continuous whole in the plant. According to their 

 position in the organism the energids become devoted to the formation of special 

 tissues for the building up of the various organ.=i. Each one of them, however, 

 whilst its actual destiny is ultimately determined by its relationships to the others, 

 is, so long as its fate as a permanent element is not fixed, a potential protophyte, 

 that is to say, it has within it all the capacities of the plant-organism to which it 

 belongs. 



Their construction out of this assemblage of protophytes — this colonial, or 

 perhaps better communal, organisation — gives to Angiosperms their power of dis- 

 carding eflete and old parts of the plant-body without mutilation, of allowing these 

 to pass out of the region of active life yet to remain without damage to the 

 organism as part of the body, of renewing and replacing members as required. 

 The response of the plant to the various horticultural operations of pruning, pro- 

 pagation by cuttings, and so forth is an outcome of this constitution. It is this 

 which gives them the power of developing reproductive organs at any part of the 

 plant-body, to cast them off when their work is done, and to renew them again and 

 again. This dispersion of the reproductive capacity in the Angiosperm is one of 

 the most striking of the properties it possesses, and is perhaps in no way better 

 shown than in the development of stool-shoots. There the energids of the cam- 

 bium, which normally produce the permanent tissue of wood and bark, and thereby 

 add periodically to the girth of a tree, give origin when the relationships 

 are changed by the cutting over of its bole to a callus from which stool-shoots 

 arise as new growths, which may ultimately produce flower and reproductive 

 organs. 



Another outcome of this organisation of the Angiosperm is its power of 

 extension and its longevity. It is potentially immortal. How far this expecta- 

 tion of life of a plant is realised in nature we have no evidence to show. Possibly 

 we may presage the longest life in the case of perennial herbs. Trees and shrubs 

 by their exposure in the air are liable to injury which must militate against long 

 life, and yet cases of trees of great age are well known to you all. 



It is this feature of the life of Angiosperms which marks them out sharply in 

 contrast with the higher members of the animal kingdom. There we have indi- 

 viduality, and consequently comparatively short life. Let me emphasise this. 



Of the VegrAahh Kingdom and the Animal Kingdom. 



The root-difference between plants and animals is one of nutrition. Plants are 

 autotrophic, animals heterotrophic. 



Whatever has been the origin of the two kingdoms, we must trace the differ- 

 entiation of plants to their acquisition of chlorophyll as a medium for the absorp- 

 tion of the energy of the sun. The imprint of its operation is borne in the 

 construction of all higher plants and distinguishes them from animals. The 

 vegetative mechanism of the plant has been elaborated upon lines enabling it to 

 obtain the materials of its food from gases and liquids which it absorbs from its 

 environment. For the plant the primary requisite has been a sufficient surface of 

 exposure in the medium whence it could obtain energy along with the gases and 

 liquids of its food. To this end the fixed habit is an obvious advantage, for the 

 question of bulk within the limits of nutrition becomes thereby not a matter of 

 moment; and an upward and a downward extension gives opportunity for the 

 creation of a larger expanse of absorptive surface. Thus it has come about that 

 the plant-organism has developed that polarity which finds expression in the pro- 

 fuse root-system and shoot-system with their localised growing points of the 

 highest forms of to-day. That the communal organisation is well fitted to this 

 mode of life requires no exposition. 



The nutritive mechanism of animals, on the other hand, has Ijecome one for 



