THE TECHNOLOGIST. [Nov. 1, 1864. 



188 ON THE REVERSION AND 



statistics the Oudh and Punjab cocoons are at least 50 to 56 per cent, 

 below the Cashmere standard, which is itself considerably below that of 

 France, we may safely say that the cocoons of the Indian-bred Bombyx 

 mori are little short of 75 per cent, below what they ought to be. 



What benefit, then, I would ask, is likely to ensue from the introduc- 

 tion into Italy of the eggs lately purchased in Cashmere by Dr. Carlo 

 Orio 1 The worms feared from those eggs will no doubt be improved 

 by the change of climate and more judicious treatment, but they wiD 

 add nothing to the health and vigour of the European stock. 



It has been justly remarked, " that there are few individuals who 

 have not watched the interesting change which takes place in the larva? 

 of the Bombyx mori, or common silkworm, from the point of its exit 

 from the egg until it has reached its full butterfly existence ; and many 

 there are who have been sadly disappointed at the mortality which 

 comes over a brood of silkworms, in a single night from some cause or 

 causes unknown, and consequently irremediable. Such epidemics are 

 continually occurring in China as well as Europe, and constitute one of 

 the greatest obstacles to the introduction of the culture of the silkworm 

 into England. What occasions this sudden decimation of these insects 

 has never been determined, but has long led to a wish, on the part of 

 those interested, that a more hardy breed of silk-producing worms could 

 be introduced into Europe, even though the produce was coarser and of 

 a worse colour than the ordinary mulberry silk." * Here, then, is a 

 further and very recent testimony to the diseased state of the worm. 



I shall doubtless be told that " the proof of the pudding is in the 

 eating," and that as silk of the best quality and worth twenty-five 

 shillings per pound has been produced in the Punjab, the worm cannot 

 possibly be diseased or have lost it constitution. 



To this I reply, that in order to test " the pudding" properly and 

 fairly, we require a judge possessed of some knowledge of what a pudding 

 ought to be. 



In the introductory remarks to my ' Monograph on the Genus 

 Attacus,' I have shown, after Kirby and Spence and other authorities, 

 that the gum from the reservoirs being conveyed to the mouth by the 

 constriction of certain muscles, passes through two small orifices in the 

 lip, and the two fibres thus formed, being taken up and twisted to- 

 gether by the hook-like processes in the mouth appointed to that office, 

 become one fibre of silk on coming into contact with the cold external 

 air. Now these two orifices in the lip are expressly appointed to the 

 purpose of regulating the thickness of the silken fibre with which the 

 cocoons are formed ; they are a provision of Nature which determines 

 the thickness of the silken thread, and that thickness, in worms of equal 

 size, will be constantly uniform, so that a large and healthy worm will 

 yield a thicker fibre than a smaller and degenerated worm. 



* ' Journal Soc. Arts/ Nov. 6th, 1863, p. 776. 



