Periodical Literature. 445 



unprofitable. Rubber hunters have traversed most of the areas 

 where rubber trees may be found. Otherwise the forests have 

 scarcely been touched except along the coast and principal rivers. 

 In Paraguay the timbers of lapacho and quebracho used by 

 Jesuit missionaries are well preserved while imported North 

 American woods decay rapidly. In Columbia the eucalyptus 

 grows very successfully. The west coast depends almost entirely 

 on North American woods because of the transportation difficul- 

 ties caused by the mountains. 



Canada Lumberman and Wood Worker. June 15, 1909. 

 BOTANY AND ZOOLOGY. 



The student of Biological Dendrology can 

 Present Problems find no more suggestive and stimulating 

 in Plant Ecology. reading than that in the series of articles 



cited below. Dr. Cowles' paper is a protest 

 against the theory of vitalism in Plant Ecology, that is, the phil- 

 osophy that plants develop structures because such structures are 

 of use to them. To cite one of his many illustrations : "Hard bast 

 and similar mechanical tissues are an undoubted source of strength 

 in plants, yet recent experiments have failed to get any significant 

 response in bast development by exposing growing tissues to con- 

 siderable tension. Bast primordia, however, are very plastic and 

 respond readily to changes in moisture. Thus, bast fibers do not 

 adapt themselves to a demand for tensile strength, although such 

 a response would be highly advantageous, but they do respond to 

 increased transpiration, although it has never been claimed that 

 bast fibers are of especial value in checking transpiration." The 

 writer points out that such terms as adaptation, adjustment and 

 regulation are misleading because they are vitalistic words which 

 imply that plants can transcend their environment and can con- 

 travene the ordinary laws of matter. 



Dr. Livingston makes a plea for more accurate quantitative 

 studies of the factors of site and for the development of more 

 accurate recording instruments. For example, there is no reliable 

 and practical instrument for measuring light intensity. The so- 

 called photometer is not a photometer at all but an actinometer 

 and is thus most responsive to the shorter light waves which are 

 not the most important in plant activity. Methods for determ- 



