ON SERICICULTURE. 107 



of eggs from Japan, and distributed them over Great Britain 

 and Ireland, so as to obtain a widely-extended trial. The 

 summer being unusually warm was inimical to a denizen of 

 the cool shady recesses of the Japanese forests. About 240 

 cocoons were all that, to my knowledge, were spun ; how- 

 everj about 1,000 fertile eggs have been obtained, and as 

 this winter will bring me another batch of eggs from Japan, 

 we will hope that a cooler season in 1869 will afford a more 

 favourable result. It is, however, of far greater importance, 

 in an early stage of the experiment, to find out the causes 

 which operate to produce the peculiar mortality of these larvae 

 and check their naturalization, than to be able to record, as 

 the French have done, successful results for several years, 

 and then a mortifying failure. And as the disease and its 

 causes can be best studied in bad seasons, I derive consola- 

 tion from the unfavourable results of last year, as enabling 

 us the better to perceive the chief difficulties which have to 

 be overcome before the acclimatization of this valuable race 

 may be pronounced a success. From my own experience of 

 the last three years, and from the details furnished to me by 

 others, I am led to think that the worm is liable to three 

 kinds of disease. 



First. In early life, in the first or second age, a small 

 per-centage of worms are apt to turn yellow, and be affected 

 with diarrhoea; they become soft, and die. This form of 

 disease has been described by French writers on silkworms 

 as the jaundice. I believe it to be due entirely to want of 

 vitality, as I have noticed that the smaller, later born and 

 weakly worms are chiefly affected thereby. 



Second. In mid-age another malady, caused, I believe, 

 entirely by too high a temperature, attacks the worms. 

 The first indications are that the vivid beautiful green tint 

 becomes dull and opake, the skin tightens at the flexures of 



