14 Dr. C. R. A. Wright's Contributions to the [Nov. 16, 



From these numbers it appears that the free base, like bromo- and chloro- 

 tetra-codeia, rapidly absorbs oxygen from the air. 



Probably there exists a compound intermediate between the hydriodate 

 just described and the original body, C 68 H 82 1 2 N 4 O 10 , 4HI ; thus one 

 batch of flakes got by two treatments with water of this original substance 

 gave the following numbers after drying at 100° : — 



0*3225 grm. gave 0*556 C0 2 and 0*153 H 2 0. 



0*3205 grm. gave 0*212 Agl. 



Another specimen obtained similarly : — 

 0*4175 grm. gave 0*269 Agl. 



Calculated. Found. 



C 68 816 46*58 47*02 



H 85 85 4*85 5-27 



I 5 635 36*24 35*75 34*82 



N 4 56 3*20 



O 10 160 9*13 



C 68 H 81 IN 4 O 10 ,4HI 1752 100 00 



It is not impossible that this substance is not a definite compound, but 

 only a mixture ; nevertheless, a free base of this composition and its hy- 

 driodate have been obtained by the action of sodium carbonate on the 

 compound C 68 H 86 1 2 N 4 12 , 4HI, from whence it appears probable that 

 the body analyzed is really a definite compound, formed by the reaction 

 C 68 H 82 1 2 N 4 O 10 , 4HI=HI + C 68 H 81 IN 4 O 10 , 4HI. 



Both the final and intermediate products have a very curious structure 

 under the microscope ; although they simulate in a high degree the ap- 

 pearance of crystals as they separate from a hot aqueous solution, yet on 

 microscopic examination they are found to consist of strings of coalesced 

 globules not unlike the yeast-plant. In qualitative reactions all the bodies 

 hitherto described are very similar : ferric chloride gives no coloration to 

 the aqueous solution of the hydriodate ; silver nitrate is reduced on standing, 

 producing a yellow tint ; nitric acid gives an intense yellow ; sulphuric 

 acid and potassium dichromate only separate iodine ; sodium carbonate 

 throws down a white precipitate scarcely soluble in excess, and soon be- 

 coming yellow, salmon- colour, and finally dark brown ; ammonia gives a 

 similar precipitate somewhat more soluble in excess, while caustic potash 

 readily dissolves the white precipitate first formed. In many of these re- 

 actions this group of codeia derivatives utterly differs from the bodies got 

 by the action of HC1 or HBr ; most of these latter derivatives give colours 

 with ferric chloride and sulphuric acid and dichromate ; all give a blood- 

 red with nitric acid, while the free bases turn more or less green by expo- 

 sure to air. 



On similarly treating with boiling water the compound C 68 H 82 1 2 N 4 6 ,4HI, 



