170 NATURAL HISTORY. • [CH. IX. 



known in commerce under the name of blue g-alls. 

 These are the produce of the first gathering, before 

 tlie fly has issued from the gall. Those which may 

 have been overlooked in the first gathering, and from 

 which the fly may afterward have emerged in its 

 perfect form, are called white galls : these are of a 

 very inferior quality, containing less of the astringent 

 principle than the blue galls, in the proportion of 

 two to three. 



The true vermilion kermes, and a variety of other 

 valuable colours or drugs have no other origin than 

 the punctures of different insects: many plants are 

 covered with them, and it seems probable that we 

 daily import from other countries commodities 

 which we might procure at home. The persons 

 who gather the kermes take the insect when ripe 

 and spread it upon linen, turning it at first while it 

 abounds in moisture twice or thrice a-day, to pre- 

 vent its heating. When there appears red powder 

 among it, they separate it, passing it through a sieve, 

 and then again spread out the grain upon the linen, 

 until more red powder becomes visible ; and the 

 same process is repeated until it ceases to yield any 

 more of this substance. 



In the beginning, when the small red grains are 

 seen to move, as they will do, they are sprinkled 

 over with strong vinegar, and rubbed between the 

 hands ; afterward, little balls are made of them, 

 which are exposed to the sim to dry. If this pow- 

 d<=.r should be let alone, without pouring vinegar or 

 some other acid liquor upon it, out of every grain 

 would come forth a little fly, which would skip and 

 wing about for a day or two, and at last, changing 

 its colour, fall down quite dead. 



Another species of the cocci produce the article 

 ©f commerce called gum-lac. The insect is of a 

 deep red colour, of the general shape of this tribe, 

 and not bigger than a louse. It infests certain trees 

 of the fig kind in the large forests of Hindostan 



