146 PROFESSOR TRAILL ON BERG-MEAL, OR MINERAL FLOUR. 



The most conspicuous figures in the powder, when highly magnified, had the 

 form of thin, translucent, elongated, elliptical bodies, longitudinally divided by a 

 less translucent septum or canal, as in fig. 1. The largest of this form measured 

 0.006 of an inch ; but their general size was 0.002 in length, by 0.0005 in greatest 

 breadth. The elliptical body fig. 1, ., with darker margins, measured 0.006 

 by 0.0005. The other c was equal to 0.0006 by 0.0005. Mixed with these, 

 I observed many tubular bodies, some of which are straight, others gently curved. 

 Fig. 2 measures 0.002 by 0.0001 inch in diameter. Fig. 3 is a double tube of the 

 same length, but twice the breadth. Fig. 4 is a slender tube, the length of which 

 I forgot to measure ; but it seemed to me about one-third, at least, longer than 

 fig. 2. Fig. 5 is of various sizes ; but one of the most perfect measured 0.002 

 in length. The spicula, fig. 6, vary greatly in size, from 0.0001 to 0.002. The 

 principal mass of the powder consists of fragments of the forms now described, 

 and of minute granules, which seemed to have a regular oval form, and could not 

 be above one thirty-thousandth of an inch in their longest diameter. 



Anxious to ascertain whether, besides these bodies which EHEENBERG would 

 consider as animal the powder does not contain vegetable remains, 1 submitted 

 a part of it to Dr GREVILLE, who has favoured me with the following remarks. 



" I have carefully examined the Berg-Meal, and find it full of siliceous re- 

 mains of minute animals. There appear to be a few forms, also, of those minute 

 Algce which have a siliceous structure ; especially the curved tubular bodies, 

 fig. 5, and possibly also the oval bodies, fig. 1. But if you consider EHRENBERG 

 as decisive authority, I can detect no form that, according to him, is not animal." 

 Dr GREVILLE is of opinion that the diatomacea are really vegetable productions, 

 and that the forms in question belong to that class of beings. Be this as it may, 

 it is sufficient to state that they are indisputably the remains of organised beings ; 

 and as the Berg-Meal contains organic matter destructible by fire, and, as I shall 

 presently shew, partially soluble in water, the peasantry of Swedish Lapland were 

 not so irrational in obstinately adhering to the secret use of their Berg-Meal, in 

 defiance of the local authorities, as we might, at the first glance of the subject, be 

 led to believe. Men accustomed by necessity to live on bark bread, found it no 

 unpalatable mixture with rye-flour ; and it has not the austere taste which the 

 bark of the pine, when best prepared, undoubtedly retains. 



According to the testimony of CONDAMINE and HUMBOLDT, the natives on the 

 banks of the Maragnon and Orinopko, during periods of scarcity, eat with impu- 

 nity a species of fuller's earth, devoid of any nutritive principle. LABILLAEDIERE 

 states, that the aborigines of New Caledonia eat in great quantities a soft steatite, 

 consisting of magnesia, lime, and oxide of iron. The negroes, at the mouths of 

 the Senegal, and the blacks, imported as slaves into the New World, are well 

 known to mix clay with farinaceous food ; but the presence of organic matter in 



