154 HATCH EXPERIMENT STATION. [Jan. 



Examination made of a great many leaves and branches re- 

 vealed no fungous or insect pest preying upon them. The 

 condition of the apple trees was similar, although not so 

 prevalent ; and in the maple the cast-ofF leaves were mature 

 ones. The exact cause of this trouble is not obvious, but 

 there can be little doubt that it was a functional disorder. 

 We have observed fine specimens of elm trees, which, after 

 a period of excessive seasons, would suddenly lose all their 

 leaves in midsummer, yet a year or two later would appear 

 as vigorous as ever. Inasmuch as the trees are not materi- 

 ally injured by the falling of a few leaves in midsummer, 

 remedial measures are not necessary. 



Over-feeding of Plants. 



The over-feeding of plants is not an uncommon occur- 

 rence at the present time, when so much concentrated fertil- 

 izer is used, and where attention is not given to the proper 

 amounts that should be employed. This trouble not only 

 occurs among florists, etc., but among those who cultivate 

 house plants as well ; and the cause of the trouble is usually 

 traceable to the fact that most people are not aware of the 

 strength of the constituents serving as plant food. The 

 normal strength of chemically pure solutions, available for 

 plants, is about one to one thousand or one to two thousand 

 parts, and when these solutions are put on at the rate of one 

 to one hundred or so, ill results must be expected to follow 

 their use. 



We now and then have specimens of abnormal plants sent 

 in to us which are merely suffering from some such treat- 

 ment. A potted specimen of a Johnsonian lily, which had 

 a number of reddish eruptions or blisters upon its leaves, 

 was sent in for examination. These reddish blisters were 

 examined under the microscope, and they showed no evi- 

 dence of fungi or insects being present. The cells, however, 

 in the vicinity of the blisters showed that they had been 

 stimulated exceedingly, which manifested itself in exces- 

 sive cell division, giving rise to the blisters ; and where this 

 action had taken place excessively the tissues were ruptured, 

 thus producing a ragged, wounded appearance. This trouble 



