NOVEMBEE 6, 1908] 



SCIENCE 



635 



Below 14° C. no observations are recorded. 

 Here, then, we have throughout the 

 whole range exactly the same primary 

 temperature relation exhibited by the pro- 

 toplasmic procedure that we should expect 

 for a chemical reaction in a test-tube. 



This division phase is only a part of the 

 life-cycle of the flagellate, and between 

 division it swims about anabolizing the 

 food material of the medium and growing 

 to its full size ready for the next division. 

 One wishes at once to know what is the 

 effect of the temperature upon the length 

 of the life-cycle. Is the whole rate of 

 metabolism quickened in the same way as 

 the particular section concerned with ac- 

 tual division? Of course a mobile flagel- 

 late can not be followed and its life-cycle 

 directly timed, but the information was 

 obtained by estimating carefully what per- 

 centage of individuals were in a state of 

 actual division at each temperature. It 

 was found that always 4 per cent, were 

 dividing, whatever the temperature. This 

 proves that the whole life-cycle is 

 shortened in exactly the same proportion 

 as the process of division at each tempera- 

 ture, and that it is just twenty-five times 

 as long. Therefore, the life-cycle is 125 

 mins. at 35° C. and 725 mins. at 15° C, 

 so that here, again, we have the physical- 

 chemical relation with a factor of 2.4 for 

 each rise of 10° C. 



In this paper of Maltaux and Massart 

 these relations are not considered as the 

 manifestation of physical-chemical prin- 

 ciples, but are regarded as reactions to 

 stimuli; and the paper contains a num- 

 ber of experiments upon the effect of sud- 

 den changes of temperature upon the 

 occurrence of division. As far as one can 

 make out from inspection of the scattered 

 literature, it does seem established that sud- 

 den changes of temperature act as stimuli 

 in the strict sense of the word. In many 



investigations one finds it stated that a 

 quick change of temperature produced a 

 certain reaction which a slow change of 

 temperature failed to evoke. Usually all 

 the phenomena are treated in terms of 

 stimulation, and the absence of reaction 

 with slow change of temperature is re- 

 garded as secondary. Were it not for the 

 specific stimulatory effects of quick change, 

 which are not difficult to comprehend as a 

 phenomenon sui generis, I hardly think so 

 general a tacit acquiescence would have 

 been extended by botanists to the view 

 that all enduring changes of velocity of 

 metabolism brought about by lasting 

 changes of temperature are stimulatory in 

 nature. 



No determination of the rate of develop- 

 ment of bacteria through a very wide 

 range of temperature seems to have been 

 made. There are various incidental ex- 

 periments which indicate values about 2 

 for the coefficient of increase of metab- 

 olism for a rise of 10° C. 



CONCLUSION 



In this attempt to assert the inevitable- 

 ness of the action of physical-chemical 

 principles in the cell, I have not ventured 

 upon even the rudiments of mathematical 

 form, which would be required for a more 

 precise inquiry. Bio-chemistry is indeed 

 becoming added to the ever-increasing 

 number of branches of knowledge of which 

 Lord Bacon wrote: 



Many parts of nature can neither be invented 

 with sufficient subtility, nor demonstrated with 

 sufficient perspicuity, nor accommodated unto use 

 with sufficient dexterity, without the aid and in- 

 tervening of the mathematics. 



To me it seems impossible to avoid re- 

 garding the fundamental processes of 

 anabolism, katabolism, and growth as slow 

 chemical reactions catalytically accelerated 

 by protoplasm and inevitably accelerated 

 by temperature. This soon follows if we 

 once admit that the atoms and molecules 



