DEVELOPMENTS IN PHILOSOPHY OF BIOLOGY 



87 



ented molecules may be several thousands 

 thick, and though this is, as Hardy says, 

 an insignificant example beside the colos- 

 sal ones furnished by the living organism, 

 yet it is the first likely explanation of 

 trophic action that has been advanced and 

 thus removes from physiology the stigma 

 of having absolutely no explanation at 

 all for such phenomena. 



Reference may also be made to the 

 monograph of Hedges and Myers (13), 

 who have collected together a great deal 

 of information about periodical reactions 

 in pure chemistry; reactions which ex- 

 hibit rhythmic pulsation or intermittency. 

 The most famous example of such a 

 reaction is probably the formation of the 

 Liesegang rings. This book forms the 

 most considerable addition of recent times 

 to the literature concerning "simulacra 

 vitae," already very considerable in ex- 

 tent. Although it is true that from a 

 philosophical point of view the signifi- 

 cance of these imitations of living proc- 

 esses can easily be overestimated, yet they 

 have a certain value, and the more they 

 accumulate, and the more complicated they 

 become, the more difficult it is to hold the 

 views of Haldane, Driesch, or Rignano. 

 It is much to be wished that some his- 

 torian would collect the many data in 

 existence about "simulacra vitae" be- 

 ginning with Roger Bacon's speaking 

 head and passing through the automaton 

 chess-players of the time of de la Mettrie 

 to the selenium dog and Lotka's mechani- 

 cal beetle. 



Finally, a word might be said with 

 advantage about the supposition that 

 the biologist is always, if the truth were 

 told, a thanatologist and that biophysics 

 and biochemistry are simply the study of 

 dead matter which had once been alive. 

 This belief is common; for example, 

 Johnstone O-9) says "Remember the 

 (easily ignored) fact that of living sub- 



stance we literally know nothing. We 

 study the behavior only of the living 

 organism. Whenever we study organic 

 substance, it is necessarily dead inert 

 material that we investigate." Such in- 

 accurate statements may surely cause 

 great misapprehension in the minds of 

 laymen. Physiology and biochemistry 

 have never been restricted to examining 

 dead animals, and as technique develops 

 they do so less and less. As instances the 

 work of Chambers (5) and others (45) 

 might be given, in which indicators 

 are injected into living cells, or Gelfan's 

 (15) micro-electrodes used in a similar man- 

 ner, or again, Seifriz's (48) determination 

 of protoplasmic viscosity by means of 

 an exceedingly minute metal ball intro- 

 duced into a single cell and then caused 

 to move towards an electro-magnet. Vies 

 (55), moreover, has determined the intra- 

 cellular pH by spectroscopic and spectro- 

 photometric methods involving no inter- 

 ference with the living cell at all. The 

 constitution of plant tissue has been ex- 

 amined with x-ray analysis by Sponsler 

 (50), and Crozier (8) has shown what 

 far-reaching conclusions about the me- 

 tabolism of living animals can be drawn 

 from a study of the effects of tempera- 

 ture upon them, as may also be seen 

 from the beautiful work of O. Glaser 

 (16), which caused no greater inconven- 

 ience to his paramoecia than getting them 

 to swim through a glass tube at different 

 temperatures . There can be no doubt that 

 as biological methods become more re- 

 fined, the injury caused to the experi- 

 mental material will become ever slighter. 



CONCLUSION 



It will not be very difficult to outline 

 shortly the direction which the trend of 

 thought in the philosophy of biology 

 is at present taking. The neo-vitalist 

 school, which some years ago seemed to 



