134 ANNUAL REPORT OF THE Off. Doc. 



peaches, or the currant bush stripped of its leaves by the currant 

 worm fails to perfect its fruit. The plant foods gathered by the 

 roots and forced to the extremities of j)lants are not in condition to 

 be used in the development of fruit or any other tissue until it has 

 been assimilated by the leaves; that is, the converting of Inorganic 

 material into organic material. The active agent in the leaf in the 

 matter of assimilation is the chlorophj'l, that which gives the green 

 color to leaves, and is so very dependent upon light for its existence. 

 We know so well the fate of potatoes sprouting in a dark cellar, or 

 seeds sprouted away from light. We know, too, the superior qual- 

 ity of the peach or apple developed in the full sunlight on the south 

 side of the tree as compared with the insipid fruits from the dense 

 and shaded portions of the tree. We have seen, too, the endeavor of 

 plants to absorb the greatest possible amount of light in the phenom- 

 enon known as heliotropism. When every leaf is turned to the sun 

 as it progresses from the east to the west in its" daily course. 



Studies like these- help us to understand the philosophy of the 

 practical problems of thinning seedlings where they crowd in the 

 row, of pruning thick-headed trees, of removing vigorous weeds, etc., 

 etc. 



Then, when we pass to the study of those special organs of plants 

 which are clustered in the llower and known as the reproductive 

 organs, we seem to be taken into the very confidence of plants 

 and are permitted to learn more of the secrets that are withheld 

 from the thoughtless and unobserving. We learn of the self-steril- 

 ity of some flowers, the prepotency of certain pollen, and the ad- 

 vantages of cross-fertilization. We can then appreciate the phi- 

 losophy of mixing varieties of fruits in the orchard and strawberry 

 bed, and of separating widely the sweet from yellow corn and the 

 melons from cucumbers. 



It seems to me that such a study of botany as I have briefly in- 

 dicated will furnish a training for the mind of the farmer and or- 

 chardist that is not unlike the training afforded the doctor in the 

 study of physiology. I believe, too, that the former is as helpful 

 to the farmer in prescribing for unhealthy plants as the latter is 

 to the doctor in his practice of medicine. 



How can we intelligently treat a plum tree diseased with the 

 Black-knot unless we know the true nature of the disease. I often 

 refer in this connection to the farmer who regarded this disease of 

 the plum as being like the "hide-bound" condition of a horse and 

 undertook to relieve a young plum tree by splitting the bark of the 

 trunk from tliie fork to the ground on three of four sides. When a 

 year later I asked him if his treatment destroyed the Black-knot, he 

 re])lied. "Yes, but it also destroyed the tree." I believe there is no 

 better way to get a farmer to properly care for his knotted plum 



