CHITIN. 35 



a suh.stauce iiisululile in Scliweizor s leaj^LMit, Jinirto wljieh hogiive 

 tijo imiue mycosin, the fli'iuf iitary cuiupusitioii l>eiuj,', moreover, 

 ascertiiiuoil to cont'Spoiid witli tlie foniiula CnIl.,^N'.,0,,j. This 

 substance is ii Imse, the chloriile of which is thi*o\vn <l<j\vu wlien 

 coiiceiitiatt'd hytlroi'hloric acid is adtlt-il to tlif a<jUeous sohition. 

 Mycosin itself is s()hil>lf in 2 t<» 3 per cent, hydrocliloric acid or in 

 very dihite acetic acid. A sohiti(jn of iotline in |x>tassiuui icxlide, 

 conUiining a trace of free aci<l, j^ives a reddish violet stiiiti. 

 According' to \Visskmnoii (I.) and E. Zanukk ( I.), zinc-iodo 

 chloritle solution varies in action in accoidance with the amount 

 of zinc clili)ride present, 50 per cent. pioducin>,' a hlue to blue- 

 violet coloration. These last reactions closely resemble those of 

 cellulose, and mi^'ht easily be mistaken, by an inexperienced 

 ob.server, as indicatinjj^ the pre.sence of that sukstiince. This 

 possibility will be referred to later on. 



A closer indication of the position to be allocited to mycosin 

 in the immense lieM (if organic nitro-^en compounds wasatforded 

 in a .second investigation of Wixtehsteix's (II.) by the discovery 

 that this substance is decomposed, on hydrolysis with 3 per 

 cent, sulphuric acid, into: «/-f;lucose as the chief product; then 

 probal)ly other hexoses as well, and then into acetic acid and an 

 undetermineil nitroj^enous organic sub.stance. Deci.sive conclu- 

 sion as to the method of combin.ition of the nitrogen in this 

 cell-membrane substance was .soon afterwards furnished by WiN- 

 TEUSTEIK (III.) through the discovery that, when heated with 

 concentrated hydrochloric acid, it yielded a ciyst:illis:ible fission 

 product, which proved identical with the hydrochloride of chito- 

 .samine, C.11,,0,.X11.,.11C1 — at that time erroneouslv t<?rme«l 

 gluco&imine, even by Winsterstein. As Winterstein at once 

 recollected, tln» s;ime behaviour is exhibited by chitin. /.»'. the 

 «ubst;ince (discovered by Odier) composing the chiton autl elyti^a 

 of insects, spiders, crabs, and other lower animals. This sub- 

 iitjince, ns was shown by (J. LKi)i)Kiiin»sK (1.) in 1876, furni.shes 

 inider similar tieatment the ••glucosamine" discovered by that 

 ol)server; and that too in the state of livilrochloride, from which 

 latter the free base, i.e. chitosamine itself, HO.C'll.. - (C 110 1 1 ) _ - 

 ('Il.XH, -Clio, was first isolated by C. A. Lobry de HruyiL 

 Tiiis led to the unexpected conclusion that the cell membrane 

 of the fiuigi (under examination) was to a greater or smaller 

 extent con.structed of chitin. If this .should be the case, then 

 the .saifl pit'parations of the cell membrane must al.so exhibit 

 the highly charai-teristic reaction for chitin, discovert»<l by 

 IIoppe-Sevleu (II.), namely, the disscx-iation of this substiiuce 

 into acetic aciil and chitosan by exjMJsure tt) fusible caustic 

 potash at iSo" C. Cliit<>s;in is basic in character, and is precipi- 

 tated from its acetic solution by an excess of caustic jHita-sh. 

 The chloride is insoluble in .strong hvtlrochloric acid. A similar 

 dissoci^ation pnxluct is already known in the mycosin prejvireil 



