No. 502] CHEMICAL MECHANICS IN LIVING PLANT 659 



owing to secondary causes the case is not so clear over 

 the whole range of temperature as that of respiration, 

 but that at medium temperatures we have exactly the 

 same relation hetween reaction-velocity and temperature. 



We may consider now some data upon the combined 

 net result of anabolic and katabolic processes. Such total 

 effects are seen in their clearest form among unicellular 

 saprophytic organisms for which we have a few data. 

 Mile. Maltaux and Professor Massart 18 have published a 

 very interesting study of the rate of division of the color- 

 less flagellate Clrilomotias paramaccium and of the agents 

 which they say stimulate its cell-division, in particular 

 alcohol and heat. 



They observed under the microscope the time that the 

 actual process of division into two took at different tem- 

 peratures. From 29 minutes at 15° C. the time dimin- 

 ished to 12 minutes at 25° C, and further to 5 minutes 

 at 35° C. The velocities of the procedure at the three 

 temperatures 10° C. apart will therefore be in the ratio of 

 1 : 2.4 : 5.76, which gives a factor of 2.4 for each rise of 

 10° C. (See Fig. 5, Division.) 



Now we are told by the investigators that at 35° C. 

 Chilomonas is on the point of succumbing to the heat, so 

 that the division rate increases right up to the death 

 point, with no sign of an optimum effect. Below 14° C. 

 no observations are recorded. 



Here, then, we have throughout the whole range ex- 

 actly the same primary temperature relation exhibited by 

 the protoplasmic 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 anabol- 

 izing 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 con- 



