390 



occasion of the recent blow. The leaves, as was })ractically the case 

 with all leaves throughout the storm area, were entirely stripped, but 

 the branches, probably because of the stripping" of the leaves and the 

 main-stems, were very little broken. It is remarkable though i am 

 not satisfied that any sequence of cause and effect is thereby indicated 

 that almost the only rubber trees which were broken were certain 

 trees at the Government Station at Nasimu, which had been tapped 

 at an early stage of their growth. Tiiis treatiiient resulted in an in- 

 crease in the size of their heads as well as of these stems and pjs^ibly 

 a correlative greater liability to damage from wiufJ." 



SYNTHETIC RUBBER. 



I'he discoveries of Professor Harries, of Kiel in synthetic rubber, 

 making turn out to be onlya nev»' method of making it from isoprene- 

 in which is polymerised on heating in ^ closed tube to above lOOc with 

 glacial acetic acid. The produce, it is noted, is " very expensive " and 

 only of scientific interest at present, but IF IT COULD BE produced 

 CHEAPLY its purity is such that it would compete with natural 

 rubber. " It is rumoured that a company is to be formed with a 

 capital of a million to start the manufacture." (Ext. Chemist and 

 Druggist, April 23, p. I2i).— -Ed. 



TOXINS. 



In the annual report of the Board of Scientific Advice for India 

 from 1908-1909 on the subject of Mr. Fletcher's article of Toxins 

 produced by plant roots, we read that Dr. Russell criticizes this work 

 and says that with regard to the field of experiments, the falling off 

 in yield which Mr. Fletcher ascribes to the exc^retion of toxin sub- 

 stances by other plants is no proof that toxin substances are excreted 

 and it is generally explained as due to lack of food or writei'. 



With reference to the watei culture experiments U may be 

 stated here that Mr. Fletcher obtained a solution of excreta by 

 growing plants in water culture and then used this solution as a 

 medium for plant growth. He found the medium to be toxic. Dr. 

 Russell says that Mr. Fletcher took no precaution to prevent tiie 

 development of bacteria and that there is no evidence to show that 

 the toxic substance was excreted by the plant. It might equally well 

 have been a bacterial product. Mr. Fletcher's contention is at 

 present not proved. 



Articles on this question of toxins have already appeared in 

 the Bulletin.— Ed. 



