the Vitality of Seeds by an Electrical Method. 



91 



Table X. — Beans of 1900 crop (Phaseolus ?) soaked in water for 

 12 hours, then incubated for 12 hours. Tested electrically 

 (+ Br. 10000) on January 28. Incubated on flannel and observed 

 on January 31 and on February 4, when they were again tested 

 electrically. 





January 28. 



January 31. 



February 4. 



Blaze. 





Blaze. 



Grermin. 



Radicle. 



No. 1 



> + 0-0050 volt. 



Yes 



Large 



+ 0-0124 



2 







No 



None 



-0-0002 



„ 3 



+ 0-0035 „ 



Yes 



Small 



-0-0023 1 



» 4 



-0'0002 „ 



No (App. Feb. 2) 



Mod. 



+ 00006 



» 5 



+ 00013 „ 



Yes 



Mod. 



-0-0006 



„ 6 



> + 0-0050 „ 



Yes 



Large 



+ 0-0050 



„ 7 



-0-0005 



No 



None 



-0-0002 



„ 8 



-o 



No 



None 







» 9 



> + 0-0050 „ 



Yes 



Large 



> + o-oioo 



„ 10 



> +0-0050 „ 



Yes 



Large 



+ 0-0080 



Conclusion. 



The physiological character of the blaze reaction is proved (1) by the 

 influence of raised temperature ; (2) by its general parallelism with 

 germination tests; (3) by the influence of lowered temperature; (4) 

 by the influence of anaesthetics ; (5) by the influence of strong electrical 

 currents ; (6) by the absence of blaze and failure of germination in the 

 case of water-logged seeds. In every instance a bean giving no blaze, 

 gave subsequently no sign of germination. 



There has been throughout these first observations a general, but not 

 faultless, correspondence, as regards magnitude, between the blaze 

 reaction and the germinative activity. The correspondence is such as 

 to make good the principal fact that the blaze reaction is a sign of life, 

 and that its magnitude is some measure of what we designate as 

 " vitality." The defects of correspondence may have been due to irre- 

 gularities in the results of the blaze test, or of the germination test, 

 or of both tests. As regards great differences of vitality, both tests 

 are obviously and in every case concordant, both replying by an 

 indubitable " yes " or " no " to the question whether there is blaze and 

 germination. As regards the lower degrees and the smaller differences 

 of vitality, the chances of disagreement between the two tests are 

 obviously greater. As regards the electrical test, it is more difficult to 

 take the measure upon the entire seed than upon its isolated radicle. 

 As regards the germination test, it is not always easy to ensure 

 identical and optimum conditions. 



Fresh and vigorous seeds manifest a large blaze response (0*0500 volt 

 or more), and germinate strongly. Older and less vigorous seeds mani- 



