VOL. v.] PHILOSOPHICAL TRANSACTIONS. 555 



are these. Lately (says he) consulting Langham's Garden of Health, I met 

 with this passage : Cast the flowers of cichory among a heap of ants, and they 

 will soon become as red as blood. Note, That Langham was not the first that 

 made or published this observation : I find it delivered by Hieronymus Tragus, 

 Hist. Stirp. 1. 1 . c. 91. Naturae miraculurti in hoc flore observare licet; siquidem 

 cumulo Formicarum abditus, coeruleum colorem in rubrum mutat, ac si terrore 

 illarum erubesceret. And before him it was taken notice of by Otho Brunsfel- 

 sius, as Johannes Bauhinus observ^es. I presently got some cichory flowers, 

 and made the experiment, and find it to be true; only he takes no notice of the 

 manner how the flowers become stained : which therefore I now send you. 

 Bare an ant-hill with a stick, and then cast the flowers upon it, and you shall 

 see the ants creep very thick over them. Now as they creep they let fall a drop 

 of liquor from them, and where that falls it leaves a large red stain. Some- 

 times they will not discolour them immediately, and at other times they 

 will do it in an instant. At first I guessed that being vexed by stirring their 

 hill, they might thrust their stings into the flowers, and through them convey 

 that acid liquor : But by bruising them, and rubbing the expressed juice against 

 the flow^ers, I find they will be equally stained. It is a thing well known that 

 ants, if they get into people's clothes, and so to their skin, will cause a smart and 

 tingling, as if they were nettled; which I conceive is done by letting fall the 

 before- mentioned corrosive liquor rather than by stinging. 



To what sort of liquor to refer this juice, I know not. I dropped spirit of 

 salt and oil of sulphur on the flowers, but they did not cause them to change 

 colour, at least not till the flowers were bruised. I likewise put salt of tartar on 

 them, and dropped thereon a little spirit of salt, which caused a sufficient fer- 

 mentation, but prevailed not to change the colour of the flowers in the least. 



This observation holds true not only in cichory flowers, but I suppose all 

 others of a blue colour. So far the Doctor. 



dissolves zinc with veheraence, and shoots, upon duly evaporating tlie solution, into inelegant crj'stals, 

 not at all like those produced with distilled vinegar. It seems to have little eftect on bismuth, or on 

 regulus of antimony, either in their metallic form, or when reduced into calces. 



Neumann's Chemical Works, by Lewis, v. 2, p. 328. N. 

 Mr. Ray's correspondent appears to have been tlie first who proved the existence of an acid liquor 

 in ants, a fact which was afterwards confirmed by various chemists, among whom Neumann and 

 Margraaf deserve particularly to be mentioned. A new and extensive set of experiments on tliis sub- 

 ject was undertaken in 1777 by Mr. Arvidson, who, in his Dissertation de Acido Formicarum, pub- 

 lished that year at Upsal, endeavoured to show that these insects contain a specific animal acid, which 

 was accordingly denominated the formicine, and afterwards tlie formic acid. From recent analysis, 

 however, it would appear that this acid (as indeed several chemists had long suspected) is not a spe- 

 cific animal acid, but an acid agreeing in its properties with some of those which are obtained from 

 vegetable substances j that it is, in fact, a compound of the acetic and malic acids. 



4 A 2 



