564 EFFECT OF RED LEAD, ETC., ON GERMINATION. [Jan. 



it is to be seen that the force of germination is in a slight degree 

 weakened by the red lead. Notwitlistanding these slight influences 

 which cannot properly be called favourable, the seeds coloured with 

 red lead afford almost always an equally high percentage of 

 germination as seed in its normal condition. Accordingly, when 

 once the protective power of red lead shall have been placed beyond 

 all doubt by exact experiments, there will be no reason why any 

 forester sliould hesitate to employ it as a preservative against birds 

 and mice. From the numerous experiments was also to be observed 

 that the coating of red lead is able to preserve the seeds a consider- 

 able time from mould fungus. When normal seed in the germinating 

 apparatus is thickly covered with blue mould, tliere is no fungus to 

 be observed on the coloured seed, nor for a long time after. It is 

 not until the later stages of the experiments that mould growths 

 appear also on the coloured seed. 



The reason of the delay and diminution of the intensity of 

 germination is doubtless to be sought in the increased difficulty of 

 swelling. This has been proved by experiments in which the seeds 

 were carefully weighed. For example, in one experiment it was 

 found that coloured seeds took up 6 '7 8 per cent, less water in the 

 course of two days than uncoloured. 



2. Experiments vjith Carbolic Acid. — Seeds were also treated with 

 carbolic water containing 1, 2i, 5, 7|, and 10 per cent, of carbolic 

 acid in numerous experiments. A general rule may be deduced 

 from them, that the greater the proportion of carbolic acid, the more 

 unfavourable is the effect of the solution on germination. A treat- 

 ment of spruce fir seed for 40 minutes with water containing 

 10 per cent, of carbolic acid proved absolutely deadly to the seed, 

 and a similar result would be experienced with all the other more 

 important conifers, except the larch. Larch seed is so thick-shelled 

 and resinous that it can suffer a lengthened treatment with carbolic 

 acid without taking any great harm. 



The experiments taught, that weak carbolic water containing 

 1 per cent, of acid, applied to the seed for half an hour, was 

 permissible — that is to say, if further experiments should prove that 

 such a treatment really preserves the seed from moles and mice, 

 which there is already reason to doubt. 



3. Experiments ivith Petroleum. — In numerous experiments petro- 

 leum destroyed from 70 to 90 per .cent, of the seed. It seems to 

 have a direct and absolutely deadly effect on the seed. From all 

 our experience we must give the most decided warning against 

 attempting to use petroleum for saving seeds from mice and birds. 



