PART I. 



PHYSIOLOGICAL STARTING POINTS FOR THE 



INVESTIGATION. 



If a physiological botanist wants to form a right decision 

 on the suitability of this or that tapping method, he will above all 

 find it necessary to decide and this at first apart from all practical 

 questions in what way the tapping cuts affect the vitality of the 

 tree, and therefore, also the renewal of latex, and whether they 

 will not sooner or later hinder the further development of the tree. 

 For if they injure the tree, its growth must after a certain time 

 be retarded, and the latex, on account of insufficient renewal, 

 must gradually deteriorate and become poorer in caoutchouc. 



A. Influence of Incisions in the Bark on the Life of the Tree. 



I think we can take it for granted that every tapping system will 

 have at least some injurious effect on the tree. For every tapping 

 incision wounds in no small degree a living part of the tree, namely 

 the bark. But how can such an interference injure the tree ? In 

 order to answer this question, which is a very complicated one, 

 certainly more complicated than may be imagined in planting 

 circles, it will first of all be necessary to refer to the grn.T.il 

 nutritive relations, which must exist between the various parts of 

 the tree, in order to insure its normal existence and growth. \\V 

 are lucky in being able to make well-founded statements about 

 these relations, and to ignore everything hypothetical, and can 

 thus base our decisions on a sure foundation. 



Two parts of the tree co-operate in providing it with the 

 nourishment that is absolutely necessary to make it live and grow : 

 the root system and the crown of the tree. 



The root-system supplies simultaneously thr imli>prnsal>lo 



