120 PARTICULAR CONSIDERATIONS ON THE 



conclusive, we may be prepared to review without surprise or 

 incredulity the well-known experiments of Mr. Crosse, which 

 seemed to result in the production of a small species of insect 

 in considerable numbers. This gentleman was pursuing some 

 experiments in crystallization, causing a powerful voltaic 

 battery to operate upon a saturated solution of. silicate of 

 potash, when the insects unexpectedly made their appearance. 

 He afterwards tried nitrate of copper, which is a deadly poison, 

 and from that fluid also did live insects emerge. Discouraged 

 by the reception of his experiments, Mr. Crosse soon discon- 

 tinued them ; bat they were some years after pursued by Mr. 

 Weekes, of Sandwich, with precisely the same results. This 

 gentleman, besides trying the first of the above substances, 

 employed ferro-cyanate of potassium, on account of its con- 

 taining a larger proportion of carbon, the principal element of 

 organic bodies ; and from this substance the insects were pro- 

 duced in increased numbers. A few weeks sufficed for this 

 experiment, with the powerful battery of Mr. Crosse : but the 

 first attempts of Mr. Weekes required about eleven months, a 

 ground of presumption in itself that the electricity was chiefly 

 concerned in the phenomenon. The changes undergone by 

 the fluid operated upon, were in both cases remarkable, and 

 nearly alike. In Mr. Weekes's apparatus, the silicate of 

 potash became first turbid, then of a milky appearance ; round 

 the negative wire of the battery, dipped into the fluid, there 

 gathered a quantity of gelatinous matter. From this Mr. 

 Weekes observed one of the insects in the very act of emerg- 

 ing, immediately after which it ascended to the surface of the 

 fluid, and sought concealment in an obscure corner of the 

 apparatus. The insects produced by both experimentalists 

 seem to have been the same, a species of acarus, minute and 

 semi-transparent, and furnished with long bristles, which can 

 only be seen by the aid of the microscope. It is worthy of 

 remark, that some of these insects, soon after their existence 

 had commenced, were found to be likely to extend their 

 species. They were sometimes observed to go back to the 

 fluid to feed, and occasionally they devoured each other. 1 



The reception of novelties in science must ever be regulated 

 very much by the amount of kindred or relative phenomena 

 which the public mind already possesses and acknowledges, 

 to which the new can be assimilated. A novelty, however 



3 See a pamphlet circulated by Mr. Weekes in 1842. For a detail of 

 further and more conclusive expei'iments, reference may be made to Ex- 

 planations, forming a Sequel to Vestiges, &c. 



