6 CULTURE OF SILKWORMS. 



appeared to eat it the same as if it had been g'ood leaf. The 

 Chinese said that the worms were quite healthy and that deaths 

 amongst them were very rare, but subsequent events showed 

 that this information was incorrect. They admitted that in con- 

 sequence of the disease they had been short of leaf, and had not 

 been able to rear as many worms as they expected. 



A microscopical examination of sections of the leaf showed 

 that the disease was caused by a fungus growing entirely with- 

 in its substance. A spore evidently settles on the under-side of 

 a leaf, throws out a thread which penetrates into the first 

 stomata it comes to, and then, finding nourishment, increases 

 within the tissues of the leaf, which becomes yellow and con- 

 siderably swollen at the centre of the spot. One or more of the 

 stomata on this swelling become much enlarged internally, and 

 filled with bright yellow spores, which eventually are forced by 

 those beneaththem out of the now expanded external orifice of 

 the stomata. 



The spores are rather irregular in form, some l)eing spheri- 

 cal and others oval. They measure about ^,,iuch in diameter. 

 In water the transparent spore case becomes distended and 

 separated from the granular yellow nucleus, which it then 

 encloses, as the white of an egg does the yolt. When placed in 

 a drop of water on a cover-glass, inverted over an open vasilined 

 cell of a microscope slide, so that evaporation is prevented, the 

 spores may be seen to swell as above stated and eventually to 

 burst ; the yellow contents then float out as separate granules, 

 Avhich each begin to swell luitil they attain nearly the size of the 

 original compound spore, and in about four hours the swollen 

 granides, which are spherical and are the true spores, begin to 

 throw out slender, distantly jointed, waved threads, sometimes 

 l)ranclied. Occasionally one or two of the yellow granules swell 

 within a mother cell and germinate, and the mycehal thread or 

 threads pierce the wall of the mother cell, which then has the 

 appearance of being an actual spore ; but I believe I am right in 

 saying that it is not so in reality. I have not been able to con- 

 tinuously watch for hours a particular cell luider the microscope, 

 as should be done in investigations of this sort, but have only 

 been able to devote spare minutes at odd times to the work, 

 therefore it is just possible that I have misinterpreted the 

 method of germination. It is nearly certain that the spores only 

 germinate when in a drop of water, and attack the leaf only, 

 when that drop happens to be on the under-side of a leaf. 



The mulberry which has been planted at Ayer Kuning was 

 introduced from China. The Chinese, however, say that they 

 have no recollection of having seen the leaf disease on the 



