478 Miss I. B. J. Sollas. On the Identification of [May 27, 



From their solubilities and their behaviour with Millon's reagent and with 

 the xanthoproteic test, Goodrich considered that the bristles of Oligochaeta 

 are evidently chitin or some nearly allied substance. But more recently 

 Schepotieff,* after a lengthy research, concludes : " Diese Eeaktionen zeigen, 

 dass die Borsten jedenfalls nicht aus einer einheitlichen Substanz bestehen, 

 sondern aus mindestens zwei. Die eine derselben zeigt die Eeaktionen der 

 Eiweisskbrper. Die andere kann schwerlich Chitin sein, wie der Mangel 

 der Zuckerbildung bei Behandlung mit Schwefelsaure ergiebt." With 

 regard to the last difficulty, the absence of sugar formation after treatment 

 with sulphuric acid, I am unable to find that it exists, for I obtained copious 

 sugar reduction with Trommer's test. Schepotieff (p. 672) dissolved the 

 bristles in 89-per-cent. sulphuric acid, kept them for 25 hours at a tempera- 

 ture of 40° to 50° C, diluted the solution with 10 times its bulk of water, 

 and kept the diluted solution at 100° C. for some hours. He then 

 neutralised with barium carbonate, and tested the solution with copper 

 sulphate and sodium hydrate. It was suggested to me by my friend Miss 

 Durham that the use of barium carbonate in place of the usual caustic 

 potash for neutralisation may have led to Schepotieff's difficulty, as the 

 precipitate, consequent on neutralisation with barium carbonate, would carry 

 down the sugar with it. At any rate, sugar is certainly present after 

 treatment with sulphuric acid, and there is no reason why one of the two 

 constituents should not be chitin. That more than one substance should be 

 present in the bristles is not surprising. I have not met with any chitinous 

 skeleton which did not give the proteid reaction to which Schepotieff alludes 

 before it was cleaned. 



Pupa cases of Pieris brassicce and P. napi, cleaned in the same way as 

 chitin, had a specific gravity of 1'400 and refractive index between 1*554 

 and 1'557. Griffith^ has examined these integuments chemically, and has 

 stated that they consist of a new animal substance which he calls " pupin.'' 

 He dissolved the skins (after they had been cleaned with potash, water, 

 alcohol, and ether) in hydrochloric acid, and precipitated from this solution 

 a substance to which he assigned the formula C14H20N2O5, and found that 

 it split when boiled with strong mineral acids into leucin and carbon 

 dioxide. Von Furth remarks that the proportions of C, H, and O point to 

 an albuminoid, but the IST-content is strikingly small. He suggests that a 

 closer investigation would be worth while, as he supposes that the products 

 of splitting, besides leucin and carbon dioxide, must have been overlooked. 



* ' Zeitschr. Wiss. Zool., 5 vol. 74, 1903, p. 674. 



t ' Comptes Eendus,' II, vol. 105, pp. 320—321, and ' Bull. Acad. Eoy. Belg.,' (3), vol. 24, 

 1892, p. 592. 



