87 



of the e<rgs of this pest, such as may «juide the farmer in his sowing 

 or i)lanting- so that the young phint may escape the ravages of the 

 young insects. 



INFLUENCE OF TEMPERATURE AND MOISTURE ON GERMINA- 

 TION. 



The influence of temperature and moisture on the sprouting of seeds 

 has been studied by Sturtevant at Cornell University (Agr. Exp. 

 Sta., Bull. Xo. 7), with results generally confirming those of De Can- 

 dolle. Sprouting occurs better with a uniform than with a variable 

 temperature, so that the method of Quetelet, which requires us tx) 

 take account of the squares of the temperatures, is no better than that 

 which considers the simple temperature. The rapidity of sprouting 

 diminishes with the decrease of temperature. The percentage of 

 seeds that sprout does not depend uj^on the uniformity of the tem- 

 perature. Sprouting takes place more rapidly in a rather dry soil, 

 but a decidedly wet soil is injurious. By soaking the seed before 

 planting it, the interval between planting and sprouting is dimin- 

 ished, but not between soaking and sprouting; hence the total time 

 required, and the total percentage of sprouting seeds is not much 

 affected by the soaking. The exposure to light during germination 

 retards some seeds, but does not affect others. Actual planting in the 

 field may give 50 per cent less germinations than given by similar 

 geeds planted in experimental pots under control. 



INFLUENCE OF LIGHT AND HEAT ON GERMINATION. 



Pauchon (1880) summarizes the results of the studies of many 

 authors on the relative influence of light and heat on the germination 

 of seeds and the growth of plants. The following section is condensed 

 from liim : 



Edwards and Colin (1834) state that in their day little was knowu 

 as to the influence of light and air on the green matter and on the 

 respiration of plants; since then, however, it ma}' be considered as 

 established that the life of a plant varies in proportion to the adapta- 

 tion of the plant to its surroundings. The study of the influence of 

 light may be said to have begun with Lavoisier, who thought that the 

 light directly combined with certain parts of the plant producing 

 the green leaves and colored flowers, and that without light there 

 could be no life. Similarly Moleschott (1850), at Zurich, affirms that 

 in general everything that breathes or moves draws its life from the 

 light of the sun. 



Boussingault (1870), controverting a statement of Pasteur, main- 

 tains that the growth of nnishrooms and mold in the dark is not an 

 exception but a confirmation of the general rule, and that if the solar 



