34 



SCIENCE 



[N. S. Vol. XXXIX. No. 992 



b^an to issue comprehensive meteorological 

 charts of the north Atlantic, somewhat simi- 

 lar to those discontinued by the United States 

 Weather Bureau in August. 



Dr. Julius Von Hann's first section of the 

 third edition of his " Lehrbuch der Meteoro- 

 kgie " is now for sale by the publisher, C. H. 

 Tauchnitz, of Leipzig, at 3.60 Marks. 



Charles F. Brooks 



Harvard University 



SPECIAL ABTICLES 



MUTATION IN TOBACCO 



Although recent work by Heribert Nilsson^ 

 and Davis^ shows that the sudden changes 

 which were observed in CEnothera Lamarckiana 

 can be logically and simply explained by as- 

 suming a heterozygous parent, one should not 

 conclude that this seriously weakens the gen- 

 eral theory of the origin of new types by 

 mutation. Even if the indirect evidence com- 

 piled by De Vries were also to be rejected, 

 there remain a considerable number of muta- 

 tions that have arisen in homozygous material 

 of known ancestry. The truth of this state- 

 ment is apparent if it is recalled that such a 

 careful investigator as Morgan has witnessed 

 the origin of over 150 such changes in Dro- 

 sophila. Controlled botanical evidence is not 

 as voluminous, though plant geneticists have 

 all observed phenomena that seem best inter- 

 preted in this manner. For this reason we 

 hope it is not out of place to describe the 

 origin of a variation that appeared in 1912 in 

 a field of Connecticut shade-grown tobacco, 

 which seems likely to be of very great com- 

 mercial value. 



The variety of tobacco grown under cheese- 

 cloth cover in the Connecticut valley is called 

 Cuban. It was first grovra. in this country in 

 1904 from seed which was brought from Cuba 

 the previous year by Mr. William Hazelwood, 

 of New York City. The crop of 1904 was 

 very variable, but Hasslebring^ has shown that 



1 Zeitschrift fiir induJctive Abstammungs- und 

 Yererlungslehre, Band 8, Heft 1 u. 2, 1912. 

 2Amer. Nat., Vol. 46, 1912. 

 3 The Botanical Gazette, Vol. 53, 1912. 



this type of variability is due largely to the 

 poor method of saving seed in Cuba. It is the 

 result of a mixture of seed from various types 

 of plants, for crossing seldom occurs naturally. 



Individual plants were selected from the 

 1904 plot which was grown from Cuban seed, 

 and self-fertilized seed produced by covering- 

 the seed head with a Manila paper bag. These 

 individual selections were grown in row tests 

 in 1905 and for succeeding years until 1909. 

 The individual rows grown from self -fertilized 

 plants presented a uniform appearance. Of 

 the earlier types all proved of little commer- 

 cial value except strain 13. One line known as 

 13-29 proved superior to all others in the- 

 value of the cured leaves. A considerable 

 number of self-fertilized seed plants were 

 saved from this line in 1908 and were used 

 for commercial planting in 1910 at the Wind- 

 sor Tobacco Growers' Corporation in Bloom- 

 field, giving a crop of uniform appearance, in 

 which no variations of importance were noted- 

 A large quantity of seed was saved from this 

 crop, although individual plants were not 

 selfed, as it seemed very improbable that cross- 

 ing would take place under the cheese-cloth 

 cover, and even if some crossing took place, it 

 was assumed that it would be between homo- 

 zygous individuals. The Cuban variety was- 

 thus selfed for five generations, and in all 

 probability for a sixth generation, and gave 

 every evidence that it was of a homozygous 

 nature. 



In 1912 about one hundred acres, or over a 

 million plants, were gro-wn from the seed of 

 the 1910 crop at the Windsor Tobacco Grow- 

 ers' Corporation. The general appearance of 

 the crop this year was very uniform, but when 

 clearing the field in the fall, one of the work- 

 men was very much surprised to discover that 

 one of the plants he had just cut do-wn was 

 very much taller than the others, and bore a 

 large number of unpicked leaves. This plant 

 was brought to the attention of the plantation 

 manager, Mr. J. B. Stewart, who recognized' 

 the possibilities of such a plant. After syste- 

 matic search two more such plants were dis- 

 covered. These plants were carefully taken 

 up and carried to the Connecticut Experiment 

 Station greenhouse in New Haven. One of 



