June 19, 1914] 



SCIENCE 



905 



tive influence of heredity and environment, 

 not in a general, but in a special way. As I 

 have been pointing out for several years, " the 

 heredity versus environment " muddle can not 

 he clarified except by making everything into 

 problems of differences. 



The study of the lower organisms may give 

 for human heredity, very erroneous conclu- 

 sions. The lower organisms are much more 

 modified by environment than are the higher. 

 If we are to make the science of eugenics accu- 

 rate and accumulative, we must in every case, 

 first decide what human differences, because 

 of their importance, are interesting; then 

 keeping the heredity factor constant, we should 

 experimentally alter the environmental; or 

 keeping the environmental the same, experi- 

 mentally alter the heredity. 



There can be no general answer to the time- 

 honored controversy; but there may be a spe- 

 cial answer to each separate, pragmatically 

 conceived question. There may or there may 

 not be. We can not tell until we try.^ 



Here it is not a general question whether 

 opportunity has had any influence or not. It 

 is a special one. Hare we a right to say that 

 there have been proportionately more great 

 men among kings than among commoners be- 

 cause of the environment of kingship? The 

 answer is that as far as we know at present 

 the differences of environment have had abso- 

 lutely nothing to do with it. 



Frederick Adams Woods 



Massachusetts Institute op 

 Technology 



occurrence of bacterial blight of alfalfa 

 in the salt lake valley, utah 

 The bacterial disease of alfalfa studied by 

 Sackett^ in Colorado has already done con- 

 siderable damage in the Salt Lake Valley, 



2 For a fuller discussion see ' ' Separating Hered- 

 ity from Environment, ' ' American Breeders Maga- 

 zine, Vol. II., No. 3, 1911, and "The Influence of 

 Monarchs," pp. 227-229 and 290-293. 



1 Society American Bacteriologists, Boston meet- 

 ing, December, 1909. Science, N. S., XXXI., 

 553, 1910. Colorado Agricultural Experiment 

 Station Bull. 158, 1910. 



Utah. So far as the writer knows, this dis- 

 ease, which is due to Pseudomonas medicaginis 

 Sackett, has not been definitely reported from 

 Utah, although Heald^ states that "what ap- 

 pears to be a similar disease has also been re- 

 ported from Utali, New Mexico, Nebraska and 

 Kansas." There is sufficient evidence to war- 

 rant the statement that the bacterial blight of 

 alfaKa has been prevalent in the Salt Lake 

 Valley for some time, and, no doubt, the poor 

 stands, as well as the many weak plants, are 

 due to this disease. It is certain that this 

 disease has caused more injury than the 

 crown gall disease [Vrophlyctis alfalfas (v. 

 Lagerh.) P. Magnus], recently reported by 

 the writer as occurring in the Salt Lake 

 Valley, and is certainly as injurious as the 

 alfalfa weevil (Phytonomus murinus Fab.). 

 In the past this disease has been mistaken 

 for smoke injury due to the smelters, and it 

 has also been reported as " alkali burn." That 

 this disease could have escaped notice is 

 singular, because the symptoms are as definite 

 as those of the pear-blight disease. 



The water-soaked, semi-transparent, yellow- 

 ish to olive-green appearance of the stems, 

 together with the presence of small droplets 

 of a thick bacterial ooze and the weakened and 

 partially drooping plants are the unmistakable 

 symptoms of the disease in the incipient 

 stages. Finally the stems become brownish- 

 discolored or blackened, and very brittle. 

 When the stems are attacked the foliage soon 

 becomes chlorotie, finally turning a dirty white 

 in severe cases. The leaves then become dry 

 and brittle. When small pieces of the tissue 

 of the diseased stems or leaves are mounted 

 in water on a slide, enormous masses of the 

 organisms may be seen by the naked eye 

 issuing from the tissues. There is absolutely 

 no difficulty in securing pure cultures. 



The presence of the alfalfa weevil in the Salt 

 Lake Valley is a factor in the distribution of 

 this disease. While it is known that stomatal 

 infections may occur, by far the greater num- 

 ber of infections take place through openings in 

 the epidermis produced by insect punctures and 

 severe frost injury. It has been noted that 



2 Phytopathology, Vol. II., No. 1, page 12. 



