942 LIFE : OUTLINES OF GENERAL BIOLOGY 



resembling the old ones? The Protozoa very probably are of poly- 

 phyletic origin, not monophyletic, and the Flagellate Infusorians 

 apart from the Ciliate. Indeed, we conceive the cell-cycle as basal 

 and ancestral to the Protozoa, and their main forms as its charac- 

 teristic phasal manifestations. 



THEORY OF VARIATION 



Many years ago we were together, as student and teacher at Edin- 

 burgh, in the laboratory of what is probably still the largest and 

 richest of university botanic gardens, with great collections and 

 many gardeners; so that we had but as it were to rub the ring for 

 attendant genii to appear with cornucopias laden with all the 

 specimens we desired, and these often "from the back" — as we then 

 called it ! But next one went to a chair of a new University College, 

 with no garden or gardener, save for lawn-mowing : so at first there 

 was nothing for it but to take off one's coat and start laying out 

 beds for natural orders around lawns previously fiowerless. In so 

 doing, came rediscovery of the great fact, too much forgotten in 

 one's leisured student-life of botanic studies and teaching, and in 

 fact since gardening in childhood — that painfully discovered by 

 Father Adam and all his field-labour descendants since — that 

 weeds grow apace, even in poor soil, and flowers need tending, 

 even in rich. Thus to make the best of the worst portion of ground 

 there was laid out a weed wilderness, of hugely exuberant Heracle- 

 ums and the like, for striking contrast of verdure with the rest. 

 Next came, and that emphatically, the simple reflection, again so 

 familiar to gardeners from time immemorial, that the well-growing 

 vegetables of a kitchen-garden, e.g. the cabbages and greens, the 

 garden-peas, the Jerusalem artichokes, the potatoes, and what not, 

 are also far more exuberantly vegetative, and less conspicuously 

 floral, than are their congeners of the flower-garden, hardy though 

 these often be, say the stocks and wall-flowers; and so for the 

 sweet-peas, the sunflowers and other composites, or the more 

 decorative Solanums ; while many of the associated and well-flowering 

 orders yield no utilisable vegetative surplus at all. In fact, then, the 

 verdant kitchen garden is so highly vegetative, in comparison with 

 that of flowers, as to be so far on the way to weed-like also. Thence, 

 again, looking out into nature, the like contrast became more and 

 more impressive, as that of grasses and trees, so vegetative in 

 growth, yet relatively inconspicuous in flowering, with the oftener 

 flowering shrubs, as these again so often surpassed by kindred 

 herbaceous flowerers; and the like difference appearing again 

 among kindred species and genera of these. Following up this simple 

 line of thought, more or less implicit throughout gardening and 



