September 11, 1908] 



SCIENCE 



349 



In 1907 there was a decided falling ofi in 

 number, with respect to diseased as well 

 as healthy plants, the proportion of the 

 former being plainly less than in the preced- 

 ing season. 



On account of the obscure nature of this 

 tjrpe of disease, its similarity to aster yellows 

 and kindred troubles, and more particularly 

 on account of the abundance and availability 

 of the material a series of observations and 

 experiments covering a number of years were 

 planned. The outcome of one of these ex- 

 periments was as follows: 



In September, 1906, a number of vigorous, 

 healthy young plants were carefully taken up 

 and transplanted to the comer of a garden. 

 They were placed close together, making a 

 continuous row four or five feet long. Next 

 plants showing early or at least not advanced 

 stages of yellows were selected and trans- 

 planted with equal care so as to form a row 

 on either side, parallel with, and about six 

 or eight inches removed from, the row of 

 diseased plants. None of the plants showed 

 any ill effects from the transplanting. In the 

 spring of 1907 nearly all of the diseased plants 

 were dead and the remainder failed to survive 

 the season. All of the healthy plants sur- 

 vived. They have shown no signs of yellows 

 to date and are now strong and vigorous. A 

 portion of the plants will now be removed 

 from the row and placed in the rows where 

 the diseased plants stood. 



It is hoped that later work upon this dis- 

 ease of a more fundamental nature may be 

 undertaken with added facilities in the shape 

 of a greenhouse for pathological purposes and 

 complete equipment for histological work. 



W. J. Morse 

 Maine Experiment Station 



A principle of elementary laboratory teach- 

 ing FOE culture students 

 DuRLNG recent years, courses for culture 

 students in the biological sciences have been 

 widely introduced into the schools and col- 

 leges of this country. The results attained do 

 not measure up to what was hoped for by 

 those who placed them there. Probably no 



one would be more ready than the better 

 teachers to admit that the average student, to 

 a discouraging degree, comes short of acquir- 

 ing that information or developing that power 

 of obtaining knowledge for himself which it 

 was planned that he should. 



The difficulty is not trivial and it is not 

 imaginary. It is one which should receive 

 serious consideration at the hands of those 

 whose business it is to teach. The present 

 paper is offered as a contribution toward its 

 solution. 



One university professor of botany expressed 

 to the writer the opinion that courses in 

 botany are justified by the fact that some who 

 are not adapted to other studies are awakened 

 and develop in scientific work. The writer 

 has known shining examples of such; their 

 proportion, however, is small, and it seems 

 self-evident that the teacher can be content 

 with nothing less than to reach and to bring 

 out the average student who comes into his 

 classes. 



The situation can best be stated by taking a 

 concrete illustration. Suppose then, a young 

 teacher vrith university training, high ideals 

 and a certain individuality. He surrounds 

 himself with his students, places material in 

 their hands and asks them stimulating ques- 

 tions whose answers they can find out. He 

 plans courses which include morphology, 

 physiology and evolutionary relationship of 

 plants. These subjects are sometimes segre- 

 gated, sometimes (as their arranger thinks) 

 ingeniously interwoven. The teaching pro- 

 ceeds through weeks and months. Looked at 

 as a whole, what is the outcome? Something 

 as follows: 



The success of certain of the lessons is im- 

 mediate and convincing. Perhaps, for ex- 

 ample, those upon the morpho-physiology of 

 seeds or upon winter buds, catch the interest 

 of the class, incite independent effort and 

 show every sign of living in the minds of the 

 student. On such days the teacher tastes that 

 fine joy which is said to be his chief reward, 

 mingled it may be with sinful pride and a 

 commiseration for students less fortunate than 

 his own. 



