142 



well-known experiments, for a period of 16 years in Oxygen, Nitrogen 

 Hydrogen, Carbon-dioxide, &c., without losing their power of germination. 



However, in the case of seed containing a certain (or a normal) quantity 

 of water there ensues, on the occasion of a rise of out-door temperature, 

 for instance in the spring-time, a Uvelier respiratory movement, mani- 

 fested by what is known to the millers as the " working " of the ware- 

 housed grain. At the same time, there ensues a rise in the temperature 

 of the seed. Becguerel's experiments have proved that, in the case of dry 

 seeds, there is also no iatermolecular respiration, for, when the seed is 

 kept in Nitrogen and in Carbonic acid, there occiirs no perceptible exchange 

 of gas. 



Romanes, with the assistance of Crookes (1893),- kept various seeds in 

 a vacuum for a period of 15 months and all the. seeds germinated. 

 Similarly Kochs (1890) and Laurent (1902) maintained seeds in a vacuum 

 for seven years without loss to their germinating power. It is, however, 

 certain that the power of germination diminishes With age and finally 

 becomes extinct. With respect to this, it would be of importance to know 

 what is the limit for the different varieties of seed. We find much matter 

 relating to this question collected in manuals, and much scattered in the 

 pages of periodicals. 



With regard to the seeds of vegetable-garden plants, we find a good 

 compilation in VUmorin " Les plantes potageres," 1891 : 648. With 

 regard to the upper limit of the duration of germinating power, surely the 

 best material is to be found in the above-mentioned treatise of Paid 

 Becquerel. According to this Work, out of 501 different old seeds subjected 

 to experiment, the seeds which germinated after the longest periods were 

 those of Nelumbo, then those which belong to the family of Leguminosae, 

 Malvaceae and Labiatae; notably seeds of Cassia bicapsularis have 

 germinated after 87 years, those of Oytisus biflorus after 84 years, &c. 

 In the experiment were included seeds as old as 192. years. The duration 

 of the capacity of germination is, therefore, obtnously far shorter than is 

 generally assumed on, the ground of many unreliable data , most of these 

 data collapse under criticism^ and we must, with Ewart,* accept a period 

 of from 150 to 250 years as the probable maximum for the duration of 

 germinating power. 



For much valuable material, which also affords an insight into the 

 coiu'se of germinating power, we are indebted to the Copenhagen Seed 

 Control Station, whose tables supply us with an indispensable auxiliary to 

 our studies. The well-known works of Stebler and Schroter, and of Stebler 

 and Volkart on the best fodder-plants, contain the most important data 

 relating to the diu-ation of germinating capacity. 



In the Budapest station extensive experiments have been made for 

 the purpose of ascertaining the conservation of germinating power of the 

 most important weed seeds buried in arable land.t In spite of the 

 difference in the methods employed, these experiments are parallel with 

 the studies which have been carried out by Beal in North America. 



How useful it would be if we had all these data at hand, collected in 

 such a manner as to enable us to detect the nature of the germinating 

 power of those species which are most important from the point of view 

 of seed-control, to enable us also, in the case of seeds of known age and 

 of known method of conservation, to make approximate deductions as to 

 their germinating capacity ; and, vice versa, to enable us, when we have 

 determined a certain grade of germinating power and know also the 

 rnethod of conservation, to draw conclusions as to the age of the seed. In 

 the law courts such problems are frequently presented to us for solution. 



I am well aware of the difficulties involved in this question, and among 

 these difficulties I will mention here only the influence of the complete 



* On the Longevity of Seeds. Proc. Roy. Soc, Victoria, &c., 21, 

 Pt. 1, 2-210. 



■] Dr. D. Kozma, Ueber das Verhalten der Unkrautsamen im Acker- 

 boden. Kiserl Kozleim. XXV., 1922. 



