BUTLEE AND HAFIZ. 171 



which they then break as stromatic bodies, on which the character- 

 istic spores and sterile hairs are formed. 



Relative susceptibility of the top and bottom of 



THE CANE. 



Experiments were recorded in the previous Memoir' to show 

 that much of the damage caused by red rot is due to inversion of 

 the cane sugar. This appears to be because gkicose is more readily 

 assimilated by the fungus, growth in solutions in which the sugar 

 was provided as glucose, being invariably better, at least at first, 

 than when cane sugar was supplied. Flasks were prepared with 

 solutions containing 10 per cent, cane sugar and glucose respectively 

 together with peptone and sodium chloride, and inoculated with a 

 loop of a suspension of spores, from a pure culture, in distilled water. 

 The growth in the glucose flasks early took the lead and maintained 

 its superiority for some weeks. More recently, Lewton-Brain' has 

 dealt with the same question in considerable detail. He found that 

 the inverting action of the fungus was considerable, but that, as 

 stated in the previous Memoir, the actual consumption of sugar was 

 small. This consumption, he found, fell entirely on the levulose. 

 Thus in one experiment, though 75 per cent, of the sucrose was 

 inverted, not one-twentieth part of this was actually consumed by 

 the fungus and this appeared to be all levulose. The inversion was 

 proved to be due to the presence of invertase, which was found both 

 in the mycelium and also in the solution in which the fungus was 

 grown. 



Since it is known that the upper portion of the cane is richer 

 in glucose, though poorer in total sugars, than the lower^, experi- 

 ments were made to compare the growth of the fungus in the top 

 and bottom portions. In the first experiment, 3 sound Striped 

 Mauritius canes were cut and brought to the laboratory. They were 

 each inoculated at a lower and an upper internode by removing 



' Butler, E. J., loc. cit., 1906, p. 7. 



2 Lewton-Braiii, L., loc. cit., 1908, p. 32. 



3 Leather, J. W. Chemical composition of sugarcane and raw sugars. Agric, Ledger, 

 No. 3 of 1897, p. 13. 



