Januart 2, 1914] 



SCIENCE 



35 



the plants survived, and bore 72 leaves, blos- 

 soming about January 1. Considerable seed 

 ■was saved from both the terminal and lateral 

 inflorescence of this plant. 



In 1913 about 5,000 plants were grown from 

 this seed. These plants were true to the new 

 type in all external characters, and differed 

 from the normal Cuban in having a some- 

 what lighter green shade to the leaves, in an 

 absence of basal suckers (lateral branches), 

 and in a practically indeterminate growth, 

 whereas the normal Cuban variety produces a 

 terminal inflorescence after producing from 

 16 to 25 leaves on the main stem. Twenty 

 plants were brought to our greenhouse in 

 New Haven; all but eight, however, were in- 

 jured during transportation. The eight un- 

 injured plants commenced to blossom about 

 the first of November, the range of leaf 

 counts per plant being from 62 to 80, with the 

 greater number around 70. These data show 

 that this tobacco mutant is breeding true, and 

 unless it behaves in a different manner from 

 other mutants, it should breed true in suc- 

 ceeding generations. 



The cured leaves are very promising, resem- 

 bling the normal variety. There is every 

 reason to believe that this new type will prove 

 of commercial value, as the yield per acre is 

 at least fifty per cent, greater than the normal 

 type. It has been named the Stewart Cuban. 



The normal Cuban seed which was saved in 

 1910 was again used for planting in 1913, and 

 over 200 acres, or two and one half million 

 plants, were grown. Although search was 

 made at the Windsor Tobacco Growers' Cor- 

 poration, which grows over 100 acres, no mu- 

 tating plants were discovered. Two mutants 

 were found at other plantations where the 1910 

 Windsor Corporation seed was used, which 

 presented the same habit of producing a large 

 leaf number. Thus, five similar mutants from 

 the same seed have been discovered, though it 

 can not be stated that they did not all come 

 from a single normal plant. The frequency 

 of the appearance of this mutation is at the 

 rate of about one plant in a million. 



This mutation must have taken place after 

 fertilization, i. e., after the union of the male 

 and female reproductive cells. If the muta- 



tion had taken place in either the male or 

 female cell before fertilization, the mutant 

 would have been a first generation hybrid, and 

 would have given a variable progeny the fol- 

 lowing season. 



Mutations of high leaf number have been 

 observed in tobacco previous to this time.' 

 Several years ago a variant with a large leaf 

 number was found in the outdoor Havana 

 type at the farm of Mr. Alsop in Avon, and 

 in 1912 a Havana plant which bore 72 leaves 

 was found at the Olds Brothers' Plantation in 

 Bloomfield. Six similar mutations were found 

 at a Windsor farm, and one at another farm 

 in Bloomfield this last season. It is of inter- 

 est to know that these mutations occurred in 

 a variety, the Connecticut Havana, which has 

 been grown in Connecticut for a period of over 

 fifty years, and which is very uniform in 

 habit. That it has been observed in different 

 sections and by different growers shows that 

 the same mutation must have taken place 

 several times. 



A similar type bearing a large leaf number 

 appeared in Maryland several years ago, and 

 is grown commercially under the name of 

 Maryland Mammoth. The Maryland type 

 was, however, the result of a cross between 

 two Maryland tobacco varieties. The muta- 

 tions which have occurred in Connecticut can 

 hardly be explained on the basis of the results 

 of a cross. 



H. K. Hayes, 

 E. G. Beinhart 



Connecticut Experiment Station, 

 New Haven, Conn. 



real and apparent nitrp'ying powers 

 In making bacteriological studies of soils 

 one of the leading factors determined is the 

 ability of the bacteria present to convert va- 

 rious forms of nitrogen into the nitrate con- 

 dition. Comparison of this ability, as exist- 

 ing in different soils, is usually made under 

 definite, more or less standard conditions. 

 This factor is spoken of as the " nitrifying 

 power " or " nitrifying efficiency." 



Of recent years the tendency has been to 

 employ the soil to be tested, or a standard 

 soU, as the medium in which the organisms 



