776 JOURNAL OF FORESTRY 



Massachusetts Agricultural College, can be trusted to give thoroughly- 

 reliable and wise information without much unnecessary language, 

 parts being naturally compilation and some parts based on personal 

 investigation. 



While this is a subject which only distantly interests a forester, there 

 is much in the book that he can read with benefit regarding tree life in 

 general. We will only refer to the very sane position the author takes 

 in discussing the question, "What shall we plant?" which in view of 

 the pine blister rust, the chestnut blight, and other specific pests, most 

 unusual weather conditions in the last few years included, has a bear- 

 ing on forestry practice. "Notwithstanding the fact that some trees 

 have suffered particularly from various causes," the author says, "we 

 believe that these should still be utilized for planting. . . . More- 

 over, affection by insects and fungus disease must not always be con- 

 sidered too seriously in judging the value of a species, since control of 

 many of them is possible with the use of modern methods. It should 

 be borne in mind that many of the pests are secondary or are sub- 

 servient to other causes." Thus the author considers the borers which 

 have been killing the cut-leaf birch secondary to drouth injury, which 

 can be prevented. The leopard moth injury to elms, as well as the elm- 

 leaf beetle, is considered secondary, and even the chestnut blight is 

 held by competent pathologists secondary to some other cause or de- 

 teriorating factors, as the death of numerous chestnuts without a sign 

 of blight lead to believe. Suitable soil conditions are in many cases 

 preventive of damage, and soil texture plays probably the most impor- 

 tant part in all tree development, producing also different types of the 

 same species. 



The chapters on winter-killing, sunscald, drought, and more espe- 

 cially the effects of illuminating gas and electricity, are based in part 

 on personal investigation, and hence are specially valuable. 



No two species of trees suffering from gas poisoning present pre- 

 cisely the same symptoms, and there is much difference in the same 

 species, the location, season of the year, and other factors having an 

 important modifying effect. 



The action of direct and alternating currents and the conditions 

 under which damage occurs are carefully analyzed. Alternating cur- 

 rents, employed for lighting purposes, are more frequently injurious 

 because of higher potential and more leakage; but low voltage (iio- 

 volt) lines are no causes of injury whatever, the cited judgment of a 

 court notwithstanding. The high voltage injury is local. The general 

 effect of the direct currents (electric railroads) is also mostly local, 



