NOTES AND ABSTRACTS. 



893 



Thirteen samples of seeds were selected so as to include representatives 

 of ten different families and twelve genera and species, as follows : — 

 Poacece : Zea Mays (Sweet Corn); Liliacece : Allium Cepa (Onion); 

 Brassicacece : Brassica oleracea (Cabbage) ; Baphanus sativus (Radish) ; 

 Apiacecz : Daucus Carota (Carrot) ; Fabaccce : Pisum sativum (Pea) ; 

 Phaseolus vulgaris (Bean) ; Violaccce : Viola tricolor (Pansy) ; Polemoni- 

 acca : Phlox Drummondii (Phlox) ; Solanacece : Lycopcrsicum esculcntum 

 (Tomato) ; Cucurbitacece : Citrullus vulgaris (Water-melon) ; Astcracece : 

 Lactuca sativa (Lettuce). The seed was all of the harvest of 1899, grown 

 in Michigan, Nebraska, Washington, California, and France, and was 

 received at the botanical laboratory of the University of Michigan on 

 January 27, 1900. The object of the inquiry was to test the effect of 

 climate, moisture, and temperature on vitality, with further experiments 

 to investigate the changes that take place in mature seeds, especially the 

 respiratory activities and the part played by enzymes. The " Geneva 

 Tester " was adopted for the germination tests, 200 seeds, or 100 in the 

 case of the larger seeds, Peas, Beans, Corn, and Water-melon, being selected. 

 The germination tests were made in a dark room, where the temperature 

 could be comparatively well regulated, and it was maintained fairly 

 constant through most tests. Germinated seeds were removed daily 

 during early stages of the tests, and a complete record of the number 

 germinating each day was kept. This point is of value, since the 

 germinative energy of a seed tells much as to its vitality. 



In February 1900 packets of seeds were distributed to eight different 

 parts of the United States, and submitted to the free influence of various 

 climates. The result proved that moisture is a very deleterious factor in 

 determining the longevity of seeds. It may almost be said that loss in 

 vitality is directly proportional to amount of rainfall. Seeds stored in 

 dry climates retain their vitality much better than those stored in places 

 with a humid atmosphere. The deleterious action of moisture is greatly 

 augmented if the temperature be increased ; and where the temperature 

 of the storage-house is raised, ample ventilation must be provided to carry 

 off the moisture liberated from the seed. For this reason seeds kept at 

 low temperatures during the winter often deteriorate in the warm weather 

 of spring. 



Most seeds, if carefully dried, can withstand long exposures to a 

 temperature of 37° C. (98°*6 F.) without injury, but long exposures of 

 from 39°-40° C. (102°-2-104° F.) will cause premature death. If the 

 seeds are kept in a moist atmosphere, a temperature of even 30° C. (86° F.) 

 will soon cause marked injury. Seeds can endure any degree of drying 

 without injury, i.e. by drying in a vacuum over sulphuric acid. Reduction 

 in water-content appears to be actually necessary if vitality is to be 

 preserved over a long number of years. But the seed-coats of course 

 harden in the process, and the germination will probably be retarded by 

 the inability of the seeds to absorb sufficient water rapidly enough to 

 induce the physical and chemical processes of germination. 



Seeds sent to countries with moist climates should be put up in air- 

 tight packages, after careful drying. Experiments undertaken with 

 (1) regular seedsmen's envelopes, (2) similar envelopes paraffined, after 

 filling with seed, at a temperature of 70°-75° C, (3) bottles closed with 



