Feb. 24, 1887] 



NATURE 



393 



from anything existing in the mineral kingdom, as to 

 warrant the establishment and perpetuation of a funda- 

 mental distinction between the sciences dealing with 

 "living" and " non-living" matter respectively. 



In the year 1S54 a very acute thinker, who at one time 

 occupied this chair, made a serious attempt to formulate 

 the distinctions which are supposed to divide living from 

 non-living matter ; but at a subsequent date, admitting 

 with characteristic candour that he had altogether out- 

 grown these ideas, Prof. Huxley argued, with great skill 

 and cogency, that " vitality " is merely a general term for 

 a set of purely physical processes, diftering only in their 

 complexity from those to which " inorganic " matter is 

 subject. 



It is a circumstance of no small significance that no 

 definition of life which has yet been proposed will exclude 

 the kind of processes which we can now show to be con- 

 tinually going on in mineral bodies. " Life," said the late 

 George Henry Lewes. " is a series of definite and succes- 

 sive changes, both of structure and composition, which 

 take place in an individual without changing its identity." 

 Mr. Herbert Spencer prefers to define life as " the definite 

 combination of heterogeneous changes, both simultaneous 

 and successive, in correspondence with external co- 

 existences and sequences.' 



If either or both of these definitions of life be accepted 

 as satisfactory, then, as I hope to demonstrate to you, the 

 minerals which build up the crust of our globe unquestion- 

 ably live. .At all events I am confident of being able to 

 show that "in correspondence with external co-existences 

 and sequences," or, in other words, as the conditions to 

 which they are subjected vary, they undergo " a series of 

 definite and successive changes, both in structure and 

 composition, without losing their identity." 



It may seem paradoxical, but it is nevertheless true, 

 that the " vitality " of minerals — I really do not know 

 what other term to use to convey my meaning — is much 

 greater than that of plants, and, a fortiori, than that of 

 animals : and this is the direct and necessary consequence 

 of their less complex and more stable chemical con- 

 stitution. 



The zoologist regards as a case of remarkable vitality 

 the recovery of snails which had been long affixed to a 

 museum-tablet, upon their immersion in warm water. 

 The botanist cites the germination of seeds taken from 

 ancient Egyptian tombs as a striking illustration of how 

 long life may remain dormant in the vegetable world. Let 

 us now turn to the mineral kingdom. A quartz-crystal 

 develops to certain dimensions, in accordance with the 

 natural laws of its being, and when the necessary con- 

 ditions of growth cease to environ it, its increase is 

 arrested. But the crystal still retains its " vitality," that 

 is, the power of further development which is dependent 

 on its particular " organisation " or molecular structure. 

 We may destroy that " organisation " and the " vitality " 

 which is dependent upon it in a single instant, by sub- 

 jecting the crystal to the action of hydrofluoric acid or of 

 an oxyhydrogen flame. But unless its "organisation" 

 and " vitality " be thus brutally stamped out, the crystal 

 and, indeed, every fragment of it retains, not the " promise " 

 only, but the very " potency of life." It may be worn by 

 wind and wave into a rounded and polished sand-grain ; 

 it may be washed from the beds of one formation, to form 

 part of the materials of a new one, and this process may 

 be repeated again and again : but after countless wander- 

 ings and unnumbered " accidents by flood and field," 

 extending over millions on millions of years, let but the 

 necessary conditions of growth again environ it, and the 

 battered and worn fragment will re-develop, in all their 

 exquisite symmetry, its polished facets, it will assume once 

 more the form of a quartz-crystal, having at least as much 

 claim to idinlity with the original one, as a man has with 

 the baby from which he has grown. 



" Life ! " " Vitality ! " These terms are but convenient 



cloaks of our ignorance of the somewhat complicated 

 series of purely physical processes going on within plants 

 and animals. " Organisation ! " Why should the term 

 be applied to the molecular structure of unAinceba or a 

 yeast-cell, and refused to that of a crystal .'' But even if 

 we choose to insist on such distinctions as these, must we 

 also make them a basis on which to establish our classi- 

 fication of the sciences .'' 



Unquestionably there are differences between the cycles 

 of change which take place in animals, plants, and minerals 

 respectively. As the animal differs from the plant in not 

 being able to build up its tissues from the simple com- 

 pounds of the mineral kingdom, so both animals and 

 plants difter from minerals in their power of growth by 

 intussusception. 



But perhaps the most striking difference of all between 

 the "vital" processes in animals, plants, and minerals, is 

 found in the rate at which they take place. .Animals, in 

 consequence of the instability of their chemical consti- 

 tution, are distinguished by an almost ceaseless activity 

 and a consequent brevity of existence. Plants, in the 

 slower rate at which their vital processes take place, 

 bridge over to some extent the tremendous gap between 

 animals and minerals. In these last the vital processes 

 are so prolonged in their manifestations, owing to the 

 stability of their chemical composition, and they are not 

 unfrequently interrupted by such enormous intervals of 

 time, that they are only recognised by the geologist. 



The cycles of change which take place in an ephemera 

 are rapid indeed as compared with those going on in the 

 oak-tree, among the branches of which it lives ; but in the 

 rocks among which the oak thrusts its rootlets, other 

 processes are going on compared with which the life of 

 the oak-tree is as " fast " as that of the ephemera compared 

 with its own. 



Nevertheless the three forms of life seem to start pretty 

 much on a level. A solution of nitre in which crystallites 

 are uniting, in obedience to the laws of polarity, to build 

 up crystals, with their regular forms, their molecular 

 structure, and their powers of further development ; a 

 solution of sugar, in which the cell of a yeast-plant is 

 living and growing ; and a third liquid with floating vege- 

 table particles, in w'hich an Aina'ba is increasing and 

 multiplying ; — these three may surely be compared with 

 one another, however unlike may appear to be the higher 

 developments in the three kingdoms to which they 

 respectively belong. 



I do not, of course, for one moment wish to suggest that 

 it is practicable, or even desirable, to attempt an extension 

 of the conventional use of the terms " life " and " organ- 

 isation." But 1 do think that it is of the first importance 

 that we should clearly recognise the fact that the dis- 

 tinctions between living and non-living matter are not 

 essential and fundamental ones, that cycles of change 

 exactly similar in almost every respect to those occurring 

 in the animal and vegetable kingdoms are equally 

 characteristic of the mineral kingdom ; though, in the 

 latter, they are more difficult to follow on account of the 

 extreme slowness with which they take place. 



When this great truth is fully recognised, the separation 

 of the biological and the mineralogical sciences will be 

 at an end, and mineralogy will begin to profit by that 

 revolution in thought and in method which has already 

 done so much for her sister sciences. 



The temporary divorce between biology and mineralogy 

 hai arisen, not from any inherent differences between 

 their aims, their methods, or the objects of which they 

 trc.it, but from the circumstance that, while the former has 

 in the last half century advanced with the stride of a 

 giant, the latter has during the satire period tottered on 

 with the feeble steps of infancy. Mineralogy is still in 

 the " pupa-stage" of its development; it is a classifica- 

 tory science, with its methods imperfect, its ta.xonomy 



