THE TECHNOLOGIST. [Nov. 1, 1864. 



178 ON THE REVERSION AND 



atmosphere, and various other enervating causes, until, at length, when 

 imported into the West, it no longer retained its natural vigour, health, 

 and original characteristics, but had become enfeebled, degenerated, and 

 sluggish, by a long system of interbreeding with debilitated stock, and 

 rendered liable, by the loss of constitution, to a multitude of diseases. 



From the time of its introduction into Europe, the treatment it has 

 experienced has been, with some modifications, nearly the same as that 

 pursued in China ; so that for an uninterrupted period of no less than 

 4,500 years, the worm has had to contend against all those unnatural 

 and purely artificial influences arising from a state of domestication, 

 which we erroneously persist in terming cultivation, without one single 

 renewal or infusion of the original healthy and natural stock from which 

 the race has descended ! Truly has it, as Darwin would say, undergone 

 " the struggle for existence ! " 



One would almost be tempted to think, that the object of cultivators 

 had actually been the destruction of the insect, for in what other 

 department would breeders so long have neglected to infuse new blood 

 into their domestic stock 1 Is it not a well-understood and long-esta- 

 blished fact, that, whether among animals or plants, an occasional 

 renewal of seed and re-infusion of the original stamina is found to be 

 absolutely necessary for the preservation of health, and of that particu- 

 lar standard of perfection which it is thought desirable to maintain ? 

 And yet with the domesticated Bombyx mori, this necessary precaution 

 has been uniformly neglected for 4,500 years ! What wonder, then, 

 that under the combined effects of bad and scanty food, want of suffi- 

 cient light and ventilation, too high a temperature, and with the con- 

 stant and unvarying interbreeding of a debilitated stock, the insect 

 should have become subject to a multitude of maladies, and threaten, 

 at no distant period, to become extinct. 



By here condemning the system of interbreeding, I must, however, 

 guard against the possibility of being misunderstood, for I am well 

 aware that in France a very senseless outcry has been raised in some 

 cpiarters against the interbreeding of brother and sister, and other near 

 relatives, as if, in a state of natural freedom, such a proceeding was not 

 the general and authorized rule. What I condemn, and in this I am 

 happy to find myself supported by such weighty authority as that of 

 M. Guerin-M6neville, is not the intercourse of near relations, but the 

 incessant interbreeding of diseased and debilitated individuals, which, 

 as " like produces like," cannot possibly do otherwise than perpetuate 

 and aggravate both disease and debi'ity. Where brothers, sisters, and 

 cousins are all healthy and of sound constitution, no bad consequences 

 will ensue from their interbreeding, for such is the established plan 

 upon which Nature acts ; but where disease exists, the breeding from two 

 deteriorated individuals, whether they be nearly of distantly related, 

 will only add fuel to the fire and perpetuate, and even aggravate, disease. 



I assert, then, that there is no such thing now in existence as a per- 



