PHENOMENA OF PLANT-LIFE. 45 



instituted to determine the circumstances which affect the 

 flow of sap from the maples, and furnished an excellent 

 report. 



It has been said that all species of flowering plants will 

 probably bleed from some part, if wounded, at some time of 

 their growth. This has not been demonstrated, and some 

 trees seem to have a wood so remarkably spongy and reten- 

 tive of moisture as to render it unlikely that they should ever 

 flow. Much effort has been made to arrive at the truth on 

 this subject concerning our common forest trees by methods 

 detailed below. 



About the middle of last March, a large number of trees 

 were selected and prepared for observation by boring one 

 half-inch hole to the depth of two inches into the wood, and 

 inserting a galvanized iron sap-spout, invented by Mr. C. C. 

 Post, of Burlington, Vt., and well adapted for use in the 

 sugar-bush. The species thus tapped, and all others named 

 in this paper, will be mentioned by their common English 

 names, which are familiar to most persons ; but, in order that 

 these may be clearly understood, a list is appended contain- 

 ing both the English and the Latin names. The following 



o o o 



were tested, as above described, for sap, viz. : hemlock, 

 black spruce, balsam fir, alder, European alder, striped 

 maple, red maple, sugar maple, shad-bush, white birch, 

 black birch, yellow birch, paper birch, hornbeam, chestnut, 

 hickory, bitternut, cornel, thorn, quince, ash, beech, butter- 

 nut, black walnut, mulberry, ironwood, white pine, yellow 

 pine, buttonwood, aspen, English cherry, black cherry, 

 mountain ash, apple, pear, peach, white oak, red oak, glau- 

 cous willow, white willow,' bass, linden, elm and grape. 

 These trees were visited every day, about noon, for several 

 weeks, the holes being renewed as often as necessary, and 

 whenever they were found flowing the number of drops per 

 minute was recorded, except in the case of such trees as 

 flowed somewhat abundantly and for a considerable time. 

 The whole amount of sap from those of the latter class was 

 carefully collected and weighed daily. A reference to the 

 table appended will give at a glance the principal results, 

 such as the dates of the beginning and end of the flow, and 

 the total amount from each- species. It will be seen that the 



