154 EXPERIMENT STATION. [Jan. 



field and laboratory. The results of these experiments will be 

 discussed later in the paper. 



Relation to Mosaic Disease. 

 It was at first thought that there might be some relation be- 

 tween the so-called " mosaic disease " and this, but from our 

 observations we have been able to find only a superficial rela- 

 tionship, i.e., as regards the distortion of the leaf in its first 

 stages. Other investigators,^ as has been previously mentioned, 

 have proved that the " mosaic disease " can be communicated 

 from one plant to another l)y inoculating a healthy plant with 

 the juice of a diseased plant, and that the new growth subse- 

 quent to the inoculation will come diseased in nearly every case. 

 This is not so in the case of sprout growth, however, as in no 

 instance were we able to bring about a diseased condition of 

 normal plants by inoculating them with juice taken from dis- 

 eased leaves. As it was impossible to carry on these inocula- 

 tion experiments in the laboratory, the work was done in the 

 field, and observations taken from time to time. 



Experiments in Inoculation. 

 In order to prove that, unlike mosaic disease, this malfor- 

 mation could not be communicated from a diseased sprout to a 

 healthy one, the following experiments were made. Two series 

 of ten inoculations each were made ; in one case diseased tissue 

 was inserted at the base of the terminal bud of normal, healthy 

 sprouts; in the second series the terminal buds of healthy 

 sprouts were inoculated with the filtered juice from diseased 

 plants. In all cases a healthy plant was inoculated with the 

 tissue or juice of a malformed plant of the same kind, i.e., a 

 maple was inoculated with juice from a diseased maple shoot, 

 etc. In not one case could we find that the trouble was either 

 contagious or infectious in character. The results of these inoc- 

 ulations are given in Table I., and from these results it is evi- 

 dent that the disease cannot be communicated from one plant 

 to another. 



> a. F. Wootls, U. S. Dept. Agr., Bur. Plant Ind., Bui. No. 18. 



