Gums, Resins, 



12 



[Jan. 1907. 



Lanadron Block.- Fairly mouldy but uot as bad as the Para. 

 Crepe.— Not mouldy. 



Biscuits.— (Parkin 1899). No signs of mould. 



The first point of interest is the susceptibility to mould of almost all 

 plantation rubbers- Manicoba plantation sheet jvas green with mould within a 

 few weeks. Mexican (biscuits) had evidently been mouldy previously and did 

 not develop any more. Assam plantation turned only slightly mouldy, but this 

 is a form which is more comparable with Ceylon Scrap. The outstanding planta- 

 tion rubber is Uganda sheet which shows scarcely a trace of mould. Ceylon 

 biscuits turned slightly mouldy wherever exposed, washed scrap was practically 

 free, and Crepe was quite free. This was very striking in the case of the Crepe 

 in table V, which was laid on the top of the Lanadron blocks. The latter became 

 covered with scattered patches of mould, but it did not flourish there as on the 

 newly cut surface of the Hard Para block. The mouldiness of the hard cure 

 Para appears to throw doubt on the efficacy of smoking or creosote, but on the 

 other hand Parkin's creosoted biscuits made in 1899, which lie next'to the hard cure 

 Para, show no signs of mould. 



Ficus rubber shows little tendency to become mouldy, but it shares this 

 comparative immunity with nearly all the wild rubbers. This is the most 

 striking feature of the series as they stand at present, and is quite contrary to our a 

 priori theories. It would have been expected that the wild rubbers, naturally 

 coagulated on the tree, or collected on the ground, and mixed with large quantities 

 of bark and earth, would have developed more mould than the more carefully 

 gathered plantation product ; yet the wild rubbers with hardly any exception show 

 only the slightest traces. They may be sticky or tacky, but they are not mouldy. 

 In spite of obvious objections, it is, I think, a fair conclusion that the wild rubbers 

 are not, in Ceylon, as susceptible to moulds as the plantation forms and the hard 

 cure Para. It might be suggested that the use of acids in coagulation favours the 

 development of fungi, but I do not think that this would affect the growth of the 

 species we have to deal with. 



The mould is quite superficial. A pile of well-made Ceylon biscuits develops 

 mould on the top biscuit and on the exposed edges, but there is no mould between 

 the biscuits. There is no evidence that the mould affects the rubber, and I should be 

 much surprised if experiment demonstrated any deterioration. It is purely a 

 question of appearance, and appearances at present rule the market. 



The particular species which develops on rubber at Peradeniya is identical 

 with that which forms the well-known greenish coating on boots, etc., during the 

 monsoon. It is not the same as the green mould which develops in England under 

 similar conditions. It occurs in two stages, the first being the green mould as usually 

 recognised, which consists of minute stalks bearing myriads of easily detached 

 spores, while the second is in the form of minute spheres containing sacks of spores. 

 The first form was formerly called Aspergillus, and the second Eurotium, but it is 

 now known that they are only forms of the same species. The species common in 

 Ceylon appears to be Eurotium candidum Speg., though the conidial stage differs 

 in some respects. The spheres of the Eurotium stage are less than one hundredth of 

 an inch in diameter, and where traces of mould are indicated in the table, it must be 

 understood that only a few of these spheres were found, scattered over the surface, 

 without any of the green mould which constitutes the first stage. They were not 

 mouldy in the ordinary sense of the phrase. 



Any damp rubber will, unless treated with a strong fungicide, be practically 

 certain to develop mould in a climate like that of Ceylon, and to avoid moulds it 

 would be necessary therefore to dry it as rapidly as possible. Crepe probably owes 

 its immunity to this condition. But the latest exp eriments prove that by creosoting 

 and blocking, rubber can be delivered in London free from mould, and the adoption of 

 this process should remove this supposed defect of Plantation rubber 



