FOEESTRY. 543 



Experiments in whicli cuts were renewed twice a day showed that the re- 

 moval of latex from the capillaries of Hevea trees takes place locally. The 

 equilibrium of the capillary action is broken down about four hours after the 

 first renewal. Examinations of ringed trees showed the presence of tyrosin or 

 the conversion of tyrosin into tyrosinase in the latex above the ring, whereas 

 beneath the ring tyrosinase alone was found. Isolated patches of bast were 

 capable of forming rubber. The circumference of Hevea trees at 10 cm., 85 cm., 

 and 1.35 meters height averaged as 1.6 : 1.13 : 1. 



Tapping and the storage of plant food in Hevea brasiliensis, L. E. Camp- 

 bell {Dept. Agr. Ceylon Bui. 16 {1915), pp. 26, pis. 6, figs. S).— The author 

 presents the results in detail of a study of two trees from the same clearing 

 which were planted in 1906 and tapped first in July, 1913. They were tapped 

 for six months on the full herringbone system, the tapping took place once every 

 third day, and one side only of the tree was tapped. 



The results of the study as a whole lead to the conclusion that the effects of 

 tapping on the trees here discussed were almost purely local. Starch was with- 

 drawn from the wood immediately behind the cut and also partially from nar- 

 row zones of bark below and on each side of the tapped area. These zones did 

 not exceed 1.5 in. in breadth and in most cases the breadth was considerably 

 less than this. The starch content of the bark was normal in most cases right 

 down to the top of the tapped area. Excepting for the localized withdrawal of 

 starch in the neighborhood of the tapping cut the food suj^ply had not disap- 

 peared from below the tapped area. 



Attention is called to the fact that care was taken in tapping not to cut the 

 cambium layer. Where careless or heavy tapping has been employed the tap- 

 ping cut extends down to, or nearly dovni to, the wood, thus bringing about a 

 complete severance of the channels of food transport at that place. In view 

 of this localized effect of not too deep tapping it is suggested that by changing 

 tapping from one part of the tree to another at intervals, the resting period of 

 each area so tapped is nearly as effective as if the whole tree were rested. 



The tapping of an old Hevea tree at Henaratgoda, T. rETCii {Dept. Agr. 

 Ceylon Bui. 13 {1914), PP- 4)- — A further report on a high-yielding Hevea tree 

 at Henaratgoda (E. S. R., 26, p. 444). The tapped tree measured 117 in. in 

 circumference at 3 ft. from the ground in August, 1914. It has been tapped at 

 short intervals over a period of 4 years, 9 months, with a total yield of 392 lbs. 

 7 oz. of dry rubber of which 220 lbs. 7 oz. was secured from renevN-ed bark. 



Notes on the history of the plantation rubber industry of the East, T. 

 Fetch (Ann. Roy. Bot. Card. Peradeniya, 5 {1914), A^o- 7, pp. 433-520). — A com- 

 pilation from the literature dealing with rubber culture, chiefly in Ceylon. 

 References to cited literature are given. 



The naval stores industry, A. W. Schorger and H. S. Betts {U. S. Dept. 

 Agr. Bui. 229 {1915), pp. 58, pis. 11, figs. 11). — This bulletin reviews the present 

 status of the naval stores industry and the progress which has been made in 

 improving the methods of collecting and distilling gum. Information is also 

 given on the supply of timber available for turpentine operations. 



The subject matter is discussed under the following general headings : Need 

 for improved methods, history of the industry in the United States, statistics of 

 production, commercial utilization of products, formation and flow of resin in 

 the living tree, principles underlying the distillation of crude gum, commercial 

 methods of collecting crude gum, relative yields secured from cups and boxes, 

 relative amounts of scrape formed by the box and cup systems, relative yields 

 from different depths and heights of chipping, effect of tui'i:)entine operations 

 on timber, quality of gum from boxed and cupped timber, commercial distilla- 

 tion of crude gum, French methods of collecting gum, French distillation 



