10 



SCIENCE 



[N. S. Vol. LIII. No. 1358 



is to say the new productions by Burbank, 

 Hansen, Patten, Beach, Hedrick, Webber and 

 many other plant breeders are not equal to 

 those foimd in nature. I need only recall 

 the many fine things the modern plant breeder 

 has produced. Of course, new types will al- 

 ways appear, as they have in the past. The 

 work accomplished, it seems to me, will 

 justify larger expenditure of money. 



In the matter of fundamental study of 

 these problems practical agriculture, horticul- 

 ture and floriculture are indebted to the 

 classic fvmdamental work of Hofltmeister and 

 Strasburger. This work led up to and ex- 

 plains the physical basis of Mendelism dis- 

 covered by Gregor Mendel, a work that is 

 most important in the breeding of new types. 

 We have had a host of botanical investigators 

 who have enhanced our knowledge of plant 

 breeding, linking it with practical work like 

 Nilsson, Johannsen, Bateson, Correns, Shull, 

 White, Webber and Emerson. Agriculture 

 and horticulture are indebted to the epoch- 

 making work of DeVries on mutation. His 

 work has set a score of botanists to work on 

 the pedigree culture work. I may mention 

 Nilsson, Johannsen and Gates especially. Pos- 

 sibly the outstanding problem of the pomolo- 

 gist in states like Iowa and Minnesota is that 

 of hardiness. In breeding experiments at the 

 present time it is necessary to set the trees 

 out and test them for a term of years, to see 

 whether or not this climate is too severe. 

 Bakke in some recent experiments has found 

 that by ascertaining the depression of the 

 freezing and the moisture content at a time 

 when all the tissues are in an active state of 

 growth, it is possible to obtain an idea of the 

 comparative hardiness of different apple trees. 

 These tests have been made upon trees in the 

 nursery as well as upon trees in an orchard, 

 10 years old, with practically the same results. 



SEED STUDIES 



After a consideration of pollination the 

 matter of seed is of importance. The first 

 great work published is that of Gartner, " De 

 fructibus Seminibus plantarum." Gartner was 

 free from the bias of those who preceded him. 



We have a truly modern work by one whom 

 we may regard as a modern man of science. 

 He made a comparative study, correctly deter- 

 mined the relation of the endosperm to the 

 cotyledon and named the embryo. We have 

 had a long line of investigators on the subject 

 of seeds. 



The practical application found expression 

 in the work of !N^obbe, Harz and others. We 

 may recall the work of Nobbe in the testing 

 of seeds at the small experiment station at 

 Tharand, which was the beginning of the ex- 

 periment stations such as we know them to- 

 day. Ifobbe did not merely do the mechanical 

 part in connection with the testing of seed, 

 but inquired into real scientific problems in 

 connection with specific gravity, and the vital- 

 ity of seeds imder different conditions of 

 storing. The germination of many seeds is 

 of special concern to the agriculturist, be- 

 cause it is important to know under what 

 conditions a seed will germinate best to bring 

 the largest returns. It is a matter also of 

 some concern for the farmer to know whether 

 weeds' seeds have a varying period of vitality 

 when buried in the soil, whether for instance 

 the seeds of Hibiscus Trionum and Ahutilon 

 Theophrasti will come up in his fields after a 

 quarter or half a century when he practises 

 rotation of crops. The vitality and structure 

 of seeds has of course received much atten- 

 tion. I need only recall the classic work of 

 DeCandolle who more than a century ago 

 studied the prolonged vitality of seeds. The 

 data secured by DeCandolle is frequently 

 quoted in text-books of plant physiology. 

 Also much later work of Becquerel, Beal, 

 Ewart and Hanlein on delayed germination, 

 as well as the work of Crocker and his stu- 

 dents like Shull, on the delayed germination of 

 seeds, like wild oats and other seeds of eco- 

 nomic importance. To Crocker we are in- 

 debted for an explanation of the delayed 

 germination of such seeds as the cocklebur. 

 Knowing that there is a delay in some seed 

 the farmer is better able to follow a rational 

 practise in the treatment of seeds. I am sure 

 that most of you are familiar with the work 

 of Schleiden and Vogel, Chalon, Malpighi, 



