162 SCIENCE AND FRUIT GROWING 



is a matter of speculation at present. The paraffins as a class 

 are remarkably sluggish in their chemical action, their name, 

 indeed, implying this (parum, affinis) ; yet they are not so inert 

 as is generally supposed. They are capable of acting, like other 

 antiseptics, on the organic compounds in the soil, increasing the 

 proportion of these which are soluble in water (p. 252 and IX, 

 App. p xxvii), and, as stated above, it has been found that they 

 combine with soaps, which are salts of various organic acids. 

 It is probable that some combination of this sort occurs between 

 the paraffin and the substances present in the cells, or in those 

 constituting the walls of the cells, and that a reduction, or 

 deoxidation, follows. The deoxidising action of paraffins is sup- 

 ported by the fact that ordinary paraffin oil will reduce the 

 higher oxides of iron to the lower oxides. If an emulsion is 

 made with paraffin by means of a basic sulphate of iron and 

 excess of lime, this basic sulphate becomes partially oxidised 

 by the air, and produces a higher oxide of iron, which is almost 

 black; but on being left to stand for some time in a closed 

 bottle, it loses its dark colour, owing to the paraffin gradually 

 deoxidising it back to ferrous oxide. 



Any action of this sort would be much facilitated by the 

 ease with which paraffin wets substances, and penetrates 

 vegetable matter (and presumably, therefore, animal matter), 

 even when no actual wetting can be observed. Thus, it was 

 found that when a thick-skinned Tasmanian pear was smeared 

 with even the semi-solid paraffin known as vaseline, this, in a few 

 weeks, penetrated the fruit sufficiently to give the whole of it, 

 even to the core, a very strong oily flavour. The liquid paraffins 

 acted more quickly, both on apples and pears, even after a 

 temporary immersion, and they hastened the decomposition of 

 the fruit as well. Thus, some observations were made by 

 smearing fruits of Scarlet Nonpareil apple with various oils on 

 December 14, and observing the intervals which elapsed before 

 partial decomposition set in. This interval, in the case of the 

 untreated apples was about three months, but under treatment 

 with 



Paraffin wax it was about 2 months 



Vaseline ,, ,, 2 



Solar distillate ,, ,, i 



Lighting oil i 



Petrol ,, ,, 2 weeks 



Naphtha ,, ,, i week 



Benzene i 



