APPLE-TREE CATERPILLAR SULPHUR AS A REMEDY. 203 



have applied has driven them from the tree; whereas it is their 

 natural habit to crawl from the tree at this time. Now in all 

 cases like this it is an easy matter to conduct an experiment in 

 such a manner that there can be no deception or mistake in the 

 result. Obviously, if sulphur, applied in the manner stated, has 

 any effect in rendering a tree repulsive to the worms infesting 

 it, it is in consequence of its being absorbed and circulated in 

 the sap to every limb and leaf of the tree. For the purpose, 

 therefore, of ascertaining the effect of sulphur upon the apple 

 tree caterpillar, I on the third of May cut off the limb of a wild 

 cherry tree on which w T as a nest, the worms of which were a 

 quarter of an inch in length, and inserted the but-end of this 

 limb in a cup of sulphur slightly moistened with water — where- 

 by the twigs and leaves would certainly become much more 

 strongly impregnated with this substance than they ever can be 

 from sulphur inserted in a hole bored in the trunk of a tree. A 

 limb containing another nest was also cut off and inserted in a 

 cup containing water only. These two nests were placed side 

 by side in my office, where they would be subject to the same 

 temperature and influences, except in the one particular speci- 

 fied. As the leaves upon the first mentioned limb became con- 

 sumed by the worms, a fresh limb the but of which had been in- 

 serted in moistened sulphur during the twelve hours preceding, 

 was placed in 'contact with it. Sulphur was also sprinkled upon 

 a part of the nest. But the worms seemed to wholly disregard 

 this, traveling freely around and over it, and soon inclosing it 

 under the newly woven tissues of their nest. At the end of nine 

 days the caterpillars in both nests were larger than any of those 

 out of doors, the temperature of the office warmed by a stove 

 upon chilly days and evenings, having evidently favored their 

 growth. At this time, May 12th, the worms which had fed upon 

 ordinary leaves were four-tenths of an inch in length; those 

 which had subsisted upon leaves impregnated with sulphur were 

 double their size, measuring 0.80 to 0.85. It was clearly appa- 

 rent, therefore, that so far from being in the least degree prejudi 

 cial to them, the sulphur had rendered them more healthy and 

 robust, rapidly accelerating their growth. And it hence is quite 

 probable that those hundreds of persons in our country who 



