98 DESIGN IN NATURE 



the germ, seed, or egg, I do not mean to affirm that all the tissues enumerated are contained in the original germ, 

 seed, or egg. Only this : that the original germ, seed, or egg is differentiated sufficiently to inaugurate the nrst 

 series of changes, and that these inaugurate others in constant and rapid succession, until the plant or animal is 

 completed. The first series of changes provides the materials and forces for the second, the second for the third, 

 and so on, according to the degree of differentiation required in each particular organism. It is imtial force 

 and matter that are primarily required. Granted these, development in specific directions proceeds as a 

 matter of course.^ 



§ i6. Neither Chemistry nor Physics can Produce Life. 



Chemistry and physics are not the whole of physiology. These sciences can conjure up an automaton, but 

 are absolutely powerless when an ovum is desired. Dumas, a leading authority in modern chemistry, thus limits 

 its province : " The chemist has never manufactured anything which, near or distant, was susceptible even of the 

 appearance of life. Everything he has made in his laboratory belongs to ' brut ' matter ; as soon as he approaches 

 life and organisation, he is powerless. . . . Organised matter, not capable of being crystallised, but destructible by 

 heat, the only matter which lives or has ever lived— this matter, a subordinating agent of the vegetating power in 

 plants, of the motion and sensation of animals, cannot be produced by chemistry ; heat does not give birth to it ; 

 light continues to engender it under the influence of h\'ing bodies." ^ 



The pretensions of the physicist may be disposed of even more cavalierly. 



No machine hitherto devised by human ingenuity at all resembles or can compare in efficiency with a living 

 organism, when the consumption of material and the amount of work done are taken as the standard of comparison. 

 A man is as far in advance of a steam-engine in this respect as day and hght are of night and darkness.^ If, then, 

 neither the chemist nor phj^sicist, nor both combined, can produce a living organism or anything even remotely 

 resembhng it, we are forced to fall back upon other than the chemical and physical forces, and the only ones we can 

 under the circumstances fall back upon are the vital. 



INORGANIC AND ORGANIC RHYTHMS 



The scheme of creation hangs together in a most extraordinary manner. The phenomena of day and night, 

 and of the seasons, which exert such a beneficial influence on plants and animals, are directly due to cosmic move- 

 ments now well understood. They are of the give-and-take order. They ensure periods of activity and repose, 

 or, more strictly speaking, periods of comparative activity and comparative repose, to plants and animals ; this 

 alternating activity and repose being essential to their health and well-being. Day and night and the seasons 

 come and go at regular and calculable intervals. Day and night give and take light. The seasons give and take 

 heat, moisture, &c. Day and night and the seasons provide, for plants and animals, what is virtually a series of 

 rhythmic movements. These movements are of primary importance in the organic kingdom, as they regulate 

 within hmits, the time of feeding, building up, assimilating, secreting, excreting, &c., and the resting and hiber- 

 nating of plants and animals. 



The give-and-take, rhythmic movements of the physical universe assume a great variety of foims. They appear 

 in the alternations of day and night and the seasons. They are seen in the rise and fall of the tides, in cycles of 

 drought and moisture, in wave movements of all kinds, such as those of light, heat, sound, &c. ; but— and this 

 is the marvel— they reappear in the rhythmic movements of plants and animals ; for example, in the spontaneous 

 to-and-fro movements of certain leaves ; the time-regulated opening and closing of the vacuoles of various water 

 plants ; contracting vesicles of all kinds ; and the respiratory and circulatory movements in animals, as witness 

 the opening and closing movements of the chest, heart, stomach, bladder, uterus, &c. 



The physical universe, under the influence of a First Cause and of Ufe, inaugurates the beginnings and the 

 building up of plants and animals ; it also, under the same influences, takes the initiative in everything that 

 pertains to their daily economy. Plants and animals are to be fed and rested ; give-and-take movements on the 

 part of the physical universe are consequently an absolute necessity. Plants breathe. During the day they take 

 carbonic acid from the air and give oxygen to it. Animals also breathe. They take oxygen from and return 

 carbonic acid to the air. Plants and animals in the matter of respiration reciprocate ; the one supplying what 



1 These views were first enunciated by me in an Introductory Lecture "On the Relation of Plants and Animals to Inorganic M»ff j 



on the Interaction of the Vital and Physical Forces," juiblished in the Lancet of November 15, 1873. ^"Atter, and 



'■ Faraday Lecture. 



' Count Rumford long ago showed how a much greater quantity of work could be performed by a horse than could be performed 1 , -t ^ 

 when employed as fuel in a steam-engine, " its food, 



