235 



step preliminary to it, and strictly analogous to the emission of the 

 tubular elongation from the lower portion of a spore when a suitable 

 medium has been attained as a preliminary to the evolution of the 

 fh*st leaf-like expansions of the young cryptogam. 



The lecture upon " The Morphology of Plants " treats upon the 

 doctrine which traces all the variously formed organs of plants to 

 modifications under certain circumstances of what, under certain 

 other circumstances, would have been a leaf. 



The fifth lecture is " About the Weather," and little else ; and the 

 following extract contains the cream of the matter, showing the con- 

 nexion of vegetation with the varying conditions of the atmosphere. 



" We have seen that heat and its varied distribution according to 

 latitude and longitude, height and depth, is the peculiar fundamental 

 phenomenon, around which the others group themselves, upon which 

 they are dependent. Most intimately is the degree of moisture of 

 the air connected with it, and warmth and moisture are the primary 

 conditions of all vegetable life. On those two principal forces, there- 

 fore, hangs almost entirely the distribution of plants over the earth. 

 The animal world follows the plants, since the vegetable feeders are 

 directly, the Carnivora indirectly, connected with determinate forma- 

 tions of plants. So that heat and cold are not the only consequences 

 of the position of the sun in regard to the earth, but also the whole 

 life existent thereon : the action of its mightiest forces in the raging 

 hurricane, which hurls four-and-twenty-pounders through the air, to 

 the invisible labour of the most minute Infusorium ; the roar of the 

 Chilian pine, and the low whisper of the northern birch ; from the 

 roar of the lion, the slayer of the gazelle, even to the pipe of the 

 mouse-hunting screech owl, whose discordant note the awakened 

 sleeper's superstition interprets as ' komm mit, komm mit ' (come with 

 me). The fox and tiger point to the barn-door fowl and the giraffe, 

 these to barley-fields and acacia-groves, these again to the corre- 

 sponding zones of Europe and to the glowing savannahs of Africa. 

 On the sun depend not only vitality and motion, but also the first ar- 

 rangement, and its shining rays are the pencils with which it paints 

 the light and shade, the glowing yellow of the arid sand, the cool 

 green of the moist meadow, with which it lays down the geography 

 of plants and animals upon the surface of the earth, and even sketches 

 the design of an ethnographic chart of the human race." — p. 126. 



The sixth and seventh lectures contain replies to the question, 

 " What does man live upon ?" To this question most people would 

 give the negative reply, Man cannot live upon air; but then, says the 



