15 



ipray, there certainly would have been no bees found on the trees so 

 treated. 



As a matter of more definite record bees were taken while working 

 the blossoms of the sprayed trees. This was done by pinching off the 

 flower cluster and dropping it with the bee on it into an insect net. Seven- 

 teen bees were gathered in this manner by the writer from one of the 

 sprayed trees in 25 minutes. Later in the day three of us gathered 36 in 

 30 minutes under the same conditions. 



Soon after gathering these two lots, they were taken to the laboratory, 

 placed under a wire cage, and given clean (containing no arsenic) syrup 

 and observed. 



At the same time 20 bees were taken from the check hive in the caged 

 experiment and run alongside these as a check. 



The results here are very significant. They show the 17 bees gath- 

 ered at II a. m. to be dead at i p. m. of the same day, and also the 36 

 gathered between three and four o'clock were all dead at 8 p. m. of the 

 same day. The check of twenty were all alive the next day at noon, and 

 ^vhen liberated flew away. 



Chemical analyses were made of all of the dead, and the records show 

 that 48 of the 53 gave a strong reaction to the test for arsenic. (At the 

 name time 20 worker bees and six drones from the check hive were an- 

 alyzed and no arsenic was found in any of them.) Five gave negative 

 results. This might be explained on the basis of the amount of arsenic 

 being so small, yet fatal, that it escaped our test. See Table I. 



Since the Gutzeit method, which is considered a delicate test, failed 

 to show a reaction for arsenic with these five bees, it is obvious that an 

 extremely small dose of arsenic may cause the death of a bee. It is not 

 likely that the five bees showing the negative test could have died from 

 natural causes, since there were no deaths from the check lot of 20 bees. 



The general conclusion which may be drawn from this experiment is 

 that a sufficient amount of poison is to be found in lead arsenate or other 

 arsenical sprays applied to the blossoms to cause a tremendous death rate 

 of bees. SUMMARY 



1. The Gutzeit method of determination of arsenic appears to be 

 sensitive enough for most doses that kill bees ; however, it is believed that 

 some very small fatal doses may escape detection. 



2. A very small amount of arsenic (less than .0000005 grams, as 2O3) 

 is a fatal dose for a bee. 



3. The time required to kill the bee with arsenic depends upon the 

 size of the dose. Some expire within one and one-half hours from the 

 time of administration of the poison, others linger on for a period of five 

 or six hours. Most of those observed to die from a dose gathered in the 

 field did so within three hours. 



4. Bees work freely on sprayed tree's in the open, even when there 

 are unsprayed trees all about. 



5. The morta:lity in the check cage was 19 per cent, as compared with 

 69 per cent in the lime-sulphur-arsenate of lead sprayed cage, and 49 per 

 cent in the sulphur -arsenate of lead dusted cage. 



6. For the sake of the bee, fruit trees should not be sprayed while 

 in full bloom. 



