INSECTS. 217 



infested by this insect, all remedies to dislodge it 

 seem futile. We have lost thousands of plants in a 

 season by its attacks. It seems, however, to infest light 

 or sandy soil more than heavy loam or clay, and seems, 

 also, to be intermittent in its attacks, often not being seen 

 for three or four years in succession, and again returning 

 and destroying all in its path. In our light, sandy soil 

 at Jersey City we suffered severely from it, but for 

 five years, in our heavy, clayey soil in Bergen, it has rarely 

 been 



CHAPTER XXXIH. 



ARE PLANTS INJURIOUS TO HEALTH ? 



If physicians are asked if plants are injurious to health, 

 three out of six will reply that they are. 



They will generally follow up the reply by a learned 

 disquisition on horticultural chemistry ; will tell you that 

 at night plants give out carbonic acid, which is poisonous 

 to animal life, and consequently if we sleep in a room 

 where plants are kept, we of necessity inhale this gas, 

 and sickness will follow. These worthies generally suc- 

 ceed in their specious reasoning, and the poor plants, that 

 have bloomed gaily all summer, are often consigned to 

 the coal cellar, for their winter's quarters, if given quar- 

 ters at all. No theory can be more destitute of truth ; 

 that plants give out carbonic acid may be, but that it is 

 given out in quantities sufficient to affect our health in the 

 slightest degree is utter nonsense. 



No healthier class of men can be found than green- 

 house operators, which makes me sometimes think that 

 plants have a health-giving effect rather than otherwise. 

 But doctors may tell us that our workmen are only at work 

 in the day-time, and that it is at night that the carbomc acid 



