48 AJ^A CHNOIDEA. 



CASE and spun, as was done by M. Bon. But we never got the length 

 ^^' of carding. Our difficulty was not in carding them or spinning 

 them thereafter, which we believe can be perfectly well done, but 

 in cleaning them for carding. The webs collected were full of 

 impurities, straws, chaff, dirt, portions of insects, &c. ; and the 

 process adopted for cleaning waste silk did not answer for the 

 webs. The process for getting rid of extraneous matter in the 

 broken cocoons of the silkworm is boiling, but in the boiling, 

 the spiders' webs boiled all away to nothing. 



Another economic use of the spider's web, is the use of the 

 strongest thread (the one that bears the web) by astronomers and 

 microscopists for the divisions of the micrometer attached to their 

 telescopes and microscopes ; the thread is drawn in parallel lines 

 and at right angles across the field of the eye-piece at equal dis- 

 tances, so as to make a multitude of cross square divisions scarcely 

 visible to the naked eye and so fine as to be no obstacle to the 

 view of the object. 



Among other merits, both spiders and their webs have been 

 supposed to be possessed of certain valuable medical properties, 

 for an account of some of which see Dr. Watson's lectures on the 

 principles and practice of physic, where he treats of ague and 

 intermittent fevers. To this day in some parts of the West of 

 England, notably the low lying districts bordering the mouth of 

 the Severn where fever and ague still maintain themselves, a 

 spider's web rolled up into a bolus and swallowed is still held 

 to be a sovereign specific for these diseases. Even yet in 

 some countries they have not been wholly expelled from the 

 regular practitioner's pharmacopoeia. We have seen a work on 

 Leprosy (Mai de San Lazaro), pubHshed so lately as 1852, m 

 Mexico, by Dr. Rafael Lucio, and another medical man, the 

 one the professor of medicine, and the other of surgery in the 

 university there, and in that work the authors recommend 

 pounded Mygales (as per prescription) as a medicine for that 

 disease, which is common in some parts of that country, and 



