Current Literature. 607 



closely limiting the number of cups per tree, has proved to be 

 highly advantageous since it prolongs the period during which a 

 crop can be worked and by exempting the young trees prevents 

 the exhaustion of the timber available for turpentining in future, 

 thus assuring stability and perpetuity to the naval store industry. 

 The author refers to the so-called "secondary resin ducts which 

 pour out crude turpentine over the wounded surface as a healing 

 balsam." In this connection the investigations of' Dr. Simon 

 Kirsch* are interesting. They appear to show conclusively that 

 the vertical strands of cells containing the resin ducts are the 

 same in character as the rays and perform the same primary 

 functions, viz: the conduction of elaborated foodstuffs to the 

 growing wood cells and the storage of food ; that the duct is 

 merely an intercellular space of schizogenous origin and owes its 

 existence to the different tensions present in the various elements 

 of the tissues; and that resin is excreted (not secreted) during the 

 vital processes of both the ray cells and their counterparts — the 

 vertical parenchyma cells, and is not a substance manufactured 

 especially for antiseptic purposes, or in traumatic phenomena for 

 healing wounds. The wounding due to chipping stimulates the 

 vital processes at the seat of injury and greatly increases the by- 

 product — resin; and in consequence there is an increase in the 

 number of ducts or passages necessary to contain it. The phe- 

 nomena which the author of this bulletin cites as confirmation of 

 the other theory are in entire harmony with the view just cited 

 and which to the reviewer seems the more likely. 



S. J. R. 



Proceedings of the Third Annual Session of the Pacific Log- 

 ging Congress. Compiled and issued by the Timberman, Port- 

 land, Oregon. Pp. 68. Illustrations 121. 



A valuable publication containing many papers of great in- 

 terest to both loggers and foresters. One of these deals with the 

 Regulations Governing the Removal of Timber from the U. S. 

 National Forests ; another with British Columbia's Forest Policy ; 



* The Origin and Development of Resin Canals in the Coniferae, witJh 

 Special Reference to the Development of Thyloses and their Correlation 

 with the Thylosal Strands of the Pteridophytes. 



Paper presented before the Royal Society of Canada at Ottawa, May, 

 1911. 



