1909.] 



Latent Life of Resting Seeds. 



437 



into the upper part of a narrow, perfectly dry test-tube, containing a known 

 volume of air, over mercury. These test-tubes had been previously sterilised 

 by dry heat in all cases, although with the thoroughly desiccated seeds this 

 precaution is not really necessary, except as a means of drying the tube. 



The tubes containing the seeds and mercury were set up vertically in a 

 shallow dish of mercury, where they were kept for from 5 to 15 days. 

 After this time had elapsed, samples of the contained air were drawn 

 into the Bonnier and Mangin apparatus, in which their composition was 

 ascertained. 



Those seeds which were found to emit no carbon dioxide in their ordinary 

 stored condition were not further tested for signs of respiration in the more 

 completely desiccated state, but the quantity of moisture was ascertained in 

 every kind of seed used. The relative amounts of water present in the 

 seeds at different stages of desiccation are set down in a special table which 

 follows the respiration tables given below. Throughout these experiments 

 the seeds used were the freshest obtainable, and several analyses were 

 made of each sample of air, the results tabulated below being the mean of 



these analyses. 



Respiration of Seeds. 



Kind of seed. 



State. 



Weight. 



Volume 

 of air. 



Time. 



Ugrms. 

 CO s per 

 grm. of 



seeds per 

 day. 



Percentage 

 volume 

 of 0, 

 absorbed 

 per day. 







grins. 



c.c. 



days 







Acacia melanoxylon 



As stored 



2 



5 



6 



0-005 



15 







6 



18 



7 



o-o 



0-07 







5 



4 



6 



o-o 



3 







5 



4 



6 



o-ooi 



0-15 







2 



2 



6 



o-o 



0-05 



Sordeum sativum (barley) 





6 



18 



7 



00 



0-014 







2 



5 



6 



o-ooi 



03 







5 



5 



6 



0-0006 



-13 





" 



5 



7 



6 







0-10 







6 



15 



6 



0-004 



15 







6 



18 





0-13 



2-5 







6 



15 



5 



0-004 



0-02 





Dried at 45° C. 



2-0 



8 



5 



o-o 



0-14 



in dry heat 















for 8 days 

















1-2 



6-5 



4 



0-0 



0-02 







1 -6 



55 



4 



o-o 



0-06 







2-0 



6 



5 



o-o 



0-02 







2 3 



6 



5 



o-o 



o-oo 







2 



5-5 



5 



o-ooi 



-12 





Further dried 



2 '0 



5-5 



5 



o -ooi 



-05 





for 3 days at 















100° C, dry heat 













VOL. LXXXI. — B. 



