Mr. A. B. Farn on the Silkworm Disease. 69 



A heap of rotting manure will attain a heat of 120° F., and the 

 decay of fallen leaves and other organic matter must help, how- 

 ever sHghtly, to raise the temperature of the superhcial layers ot 

 the soil. The oxidation of pyrites, which we know will some- 

 times generate heat sufficient to set the spoil-heaps at collieries 

 on fire, is helieved to affect the temperature in mines, ihe 

 crushing of rock by local strains also develops heat, and is 

 believed to be the source of volcanic action. All these sources of 

 heat, however, like other forms of energy on the earth, may be 

 traced back to one or other of two sources, viz., the sun s radia- 

 tion and the earth's original stock of energy. 



111.— The Silkwobm Disease ; its Cause and Prevention. 



By a. B. Faen. 



(Bead April 12th, 1893.) 



I have been honoured by a request to read a paper before your 

 Society, and have thought that, in complying with that request, 

 I would try to interest you by placing before you as concisely as 

 possible an account of Pasteur's researches as to the cause, and 

 prevention, of the silkworm disease, rather than attempt any- 

 thing original. Although the rearing of silkworms "^ ti"S 

 country can scarcely be called one of the industries, yet the 

 results of silkworm rearing in other countries must indirectly 

 interest the commerce of this country. No less than £2,000,UUU 

 sterling is the value of the silk raw or manufactured imported 

 into this country annually. There being no large ^^eariug ot 

 silkworms here would seem to account for the tact that M. 

 Pasteur's report on the disease does not seem to have received 

 very general attention in this country, nor, so far as my recol- 

 lections carry me, does there seem much need to intervene as 

 regards that particularly hardy race of silkworms which is stii , 

 I believe, occasionally reared in this country. In one s school- 

 days, I remember, each boy would at certain periods turn him- 

 self into a sort of perambulating incubator, carrying during the 

 daytime, in his waistcoat pocket, or even next his skm, a small 

 piece of flannel containing some score or more silkworms eggs, 

 and at night trying to maintain a more or less uniform tempera- 

 ture by placing them under his pillow. Then, too, with childish 

 impatience, he would, if a worm had but the temerity to show 

 his black head through the side of an ovum, endeavour to assist 

 nature and bring about a premature delivery by the aid ot a 



