Department of Plant Physiology. 537 



The results of these experiments demonstrate conckisively, it would 

 seem, that the use of- tar in no way prevents germination. It might be 

 further stated that germination was not retarded by the use of tar in 

 the experiments above mentioned. Again, varying quantities of the 

 tars were also employed with similar results. In other experiments the 

 seeds were planted in moist paper and compared with control experi- 

 ments under similar conditions. In no case was any injury by tar 

 demonstrated. The same results were secured when the treated seeds 

 were spread out and permitted thoroughly to dry before being planted. 

 It was not expected that the anilin or pyridine solutions would be 

 worthy of further consideration should the experiments with the coal 

 tar prove effective. Some surprise, however, was felt at the result of 

 the use of turpentine, for the experiments demonstrated that a protracted 

 treatment with this substance is extremely injurious. Turpentine should, 

 therefore, be avoided. 



(j) As a result of our own experiments it is not possible to say that 

 the use of tar will effectively deter crows, since no observations could 

 be inade upon the effect of the treatment in repelling these birds. It 

 was possible, however, to determine that tar is obnoxious to fowl. A 

 quantity of seeds treated with varying amounts of both coal tar and 

 pine tar was offered to a coop of hens furnished no other food. Dur- 

 ing the first day the seed treated by either tar preparation was un- 

 touched, but during the second day a considerable part of the corn 

 treated with pine tar was eaten. At the end of the second day the 

 seed treated with coal tar had not been touched. All seed treated 

 and employed in the experiment just mentioned was permitted thor- 

 oughly to dry before being placed in the coop. Practical growers who 

 have tried the use of tar as a deterrent assert that crows will not 

 eat the seed thus treated, and the above experiment is a further indi- 

 cation that birds generallv would not be readilv induced to eat such 

 seed. It stands to reason that if a bird has established the habit of 

 digging up seed corn for food, it will continue to destroy a certain 

 amount of seed by digging it up, before becoming discouraged with 

 the locality for furnishing a meal. 



Seeds which had been treated with a coal tar were also exposed in 

 a room where mice had proved a nuisance. None of the corn thus 

 treated was touched. Some pots in which treated corn had been planted 



