18 



enormous extension of the investigation, and on an 

 average 25 plants were taken for each experiment. 



Every experiment has its sériai letter and a number, 

 while the observations during the experiment were noted 

 down by fllling in forms previously hectographed. 



Séries A, experiments 1 — 222, extending from October 

 20"' to December 31'' 1909, includes preliminary experi- 

 ments only on the material and the influence ofexternal 

 conditions, température excepted. Paragraphs 6 and 8 are 

 chiefly concerned with thèse experiments. 



Séries B, experiments 1 — 81, extending from January V* 

 to February 19"' 1910, also includes preliminary experi- 

 ments, chiefly on the purity of the atmosphère and the 

 influence of the thermostat. Only the first détermination 

 of the presentation-time at 0° C, after one hours' preli- 

 minary warming, and a few figures at 30° C, after one 

 hours' preliminary warming, are also used later on. 



Ail other experiments mentioned hère belong to séries C, 

 experiments 1 — 374, extending from Febrnary 24.'*' to 

 August 12"' 1910. 



In order to give a true idea of the method employed 

 by me I hère describe one détermination of the presentation- 

 time in détail, the détermination of the presentation-time 

 after remaining 4 hours at 30° C. I therefore reprint hère 

 the protocols of the experiment with ail détails they 

 contain. 



C. Experiment 25. Date 11— III— 1910. 



Stimulation-time : 3'30". Temp.: 30° C. "/o 100. 

 Vessel: 4, 5, 6. Age: 4 days. Length: 10 — 25 mm. 

 Temp. of room : 21° C. Humidity : 75°. 

 In thermostat: at 4. Preliminary warming: 240'. 

 Horizontal : 8— 8.3'.30". 



