374 



[November, 19i2. 



Experiments to test the relative vitality of seed from tapped and 

 untapped trees were carried out at Peradeniyain 1907. A sample of seeds 

 from a consignment just about to be exported was sent in for report, and 

 the subsequent experiments with Peradeniya seed were undertaken 

 primarily to deteimine whether the weight of the seed gave any 

 criterion as to its germinative capacity. Consequently, the seeds were 

 kept under conditions which approximated to ordinary estate practice. As 

 stated in the Circular on the subject, they were kept in open dishes in the 

 laboratory : they were not packed in charcoal or preserved in any way. 

 The results showed that the seed from the tapped trees retained their 

 vitality longer than the seed from the untapped trees. Similar experiments 

 have been carried out by Spring, but with the seeds packed in charcoal, 

 as for export, in tins each containing 200 seeds. Under these conditions, 

 the seed from untapped trees showed a greater percentage germination 

 during the period of the experiment (10 weeks) than the seed from the 

 tapped trees. Seeing that tha conditions were altogether different, a diffe- 

 rent result is not so surprising. It would be interesting to have a repeti- 

 tion of the two experiments on the same samples of seed to ascertain 

 whether the difference is really due to the manner in which the seeds were 

 kept. Unfortunately, Spring made no preliminary test of the germinative 

 capacity of his seeds ; and bis figures would seem to show that his seed 

 from tapped trees was originally of bad quality. The percentage germin- 

 ation after being packed 3 weeks was only 33. Considering that the bulk 

 of the Hevea seed sold is from tapped trees, it would seem evident that 

 the usual percentage germination is greater than that. 



Information with regard to the weight of Hevea seed is gradually 

 approximating to uniformity, and it is becoming more and more evident 

 that the discrepancies between previous accounts were due in some cases 

 to errors of experiments and in others to abnormal samples. Carruthers 

 weighed a small number of seeds at Peradeniya, and subsequently pub- 

 lished his results in the Agricultur al Bulletin of the Straits, etc ; he found 

 that 414,000 seeds would be required to yield a ton of kernels, but the seeds 

 were weighed fresh and no allowance made for drying. 



Experiments in Ceylon in 1907 showed that, in round numbers, 700,000 

 seeds would be required to furnish a ton of kernels ; but actual trials on 

 estates have proved that with unsorted seed from regularly tapped trees 

 the number is about a million. In the F. M. S., Lewton Brain has recent- 

 ly made experiments which lead him to deduce that the number required 

 will be about 533,000. The weight of 1,000 fresh seeds was 8 lbs. 6 ounces, 

 the weight of the shells alone being 3 lb 2 oz ; this gives a total of 426,700 

 seeds required to produce a ton of fresh kernels, and allowing 20 per cent, 

 for loss on drying brings the number inquired to 533,000. 



In the Ceylon determination, the weight of 1,000 fresh seed was 

 assumed to be 8 lbs. As the F. M. S. determination was based on seeds 

 weighing 8 lb. 6 oz. per thousand, that would account for a difference of 

 about 10 per cent, in the estimates. But another difference arises from 

 the fact that Lewton-Brain assumes that the loss of weight on drying is 

 20 per cent, of the kernel, whereas the Ceylon figures show that it is 20 

 per cent, of the whole seed, and the shell loses very little. 



The weight of a single Hevea seed, of course, varies enormously, but 

 over a aeries of large samples the average weight works out fairly 



