36 THE CELL MEMBRANE OF EUMYCETES. 



by Gilson in 1894; and as a matter of fact, chitosan and 

 mycosin are identical, and can be isolated by the same method, 

 both from animal chitin and the cell membrane of fungi. In 

 this manner it was proved that chitin is also present in the 

 fungoid kingdom, and is not, as was formerly supposed, of ex- 

 clusively animal origin ; and indeed the proof was strengthened J 

 by E. GiLSON (III.) and E. Winterstein (IV.) isolating chitin, 

 as such, from Agaricus campestris. The nitrogen content of 

 this substance was determined by these workers as 6.24 per 

 cent., a value agreeing fairly well with the 6.01 per cent, calcu- 

 lated from the formula (OisH3oN20^2) ^^t up for animal chitin 

 by G. Stjcdeler (I.) and confirmed by T. Araki (I.) in 1895. 

 On the basis of this formula the two hydrolytic reactions above 

 referred to may be expressed by the equations : — 



C18H30N2O12 + 2H0O = C14H06N2O10 + 2C2H4O2 

 Chitin in the Chitosan Acetic acid 

 potash 

 C14H26N2O10 + 2H2O = 2C6H13NO5 + C2H4O2 

 Chitosan in the Chitosamine Acetic 

 cone. HCl acid 



It may be mentioned that chitosamine, and even chitin, can 

 be split up by the prolonged action of concentrated hydrochloric 

 acid into ammonia and a sugar : — 



CeHiiOo. N H2 + H2O = NH3 + CsHiaOs 



to which Berthelot has given the name chitose. The formation 

 of this sugar by the action of concentrated hydrochloric acid on 

 preparations of the cell membrane of fungi has already been 

 observed by St.edeler (I.) without, however, the nature of the 

 reaction having been recognised. 



Bearing in mind the fact that Dreyfuss employed concen- 

 trated potash at 180° C., tnider which circumstances the chitin 

 present would be converted into chitosan, the latter — according 

 to Gilson — then behaving like cellulose in presence of certain 

 reagents, it will be readily understood why Dreyfuss arrived at 

 the conclusion that he had to deal with pure cellulose. Accord- 

 ing to the results obtained by Wisselingh (L), the same con- 

 version, and consequently the same liability to deception, also 

 occurs when chitin is exposed for a considerable time to the- 

 action of dilute (7 to 8 per cent.) caustic potash at the ordinary 

 temperature, i.e. the same treatment as employed by Richter in 

 purifying the cell membrane preparations. 



Finally, it is not inappropriate to recall that the formula 

 given above for chitin is not yet entirely beyond dispute. It 

 cannot at present be definitely stated whether the relative- « 



values of the bodies taking part in the foregoing reactions are 1 



accurately represented by the equations laid down by Araki ; in || 



fact we have still to face the possibility of there being a whole 



