CHEMISTRY OF THE LEUCOMAINES. 309 



As to the origin of th's eul stance in the- organl.-m v< i y 

 little has Inn kixwn up to within a i \v yens, exe<j>t so 

 (in- a- it I.:-- Inn sl.e> \\ n to I c. t< Hi th( r with othe r in< mhers 

 of (li:s group, a (i; ii-!iiii\ j re;duet in the retrograde meta- 

 morphosis oi' nitnge nous foods and tissues. In the case of 

 the lower air'mals it is evidently the (iid-produet of all 

 change-, 'ni'smueh as it is excreted as such. Our knowledge 

 :;- to the immediate origin of this and the other allied l:ases 

 has lately hern exteneled by the brilliant researe-hcs of 

 K OSS EL on the decomposition products of nuelein, in whirli 

 he has shown that this essential constituent of all nucleated 

 cells whether animal or vegetable 1 , dee oniposrs under the 

 ae-tion of water or dilute aeicls into adenine, guanine, hypo- 

 xanthine, and xanthine. We know that the first two bases 

 are readily converted by the aetion of nitrous ae-id into the 

 other two ; that is to say, an NH group in these bases is 

 re-placed l>y an atom of a change which it is not at all 

 unlike-ly take s place in the tissues, perhaps in every cell 

 nucleus. That such a change is quite probable is shown by 

 the putrefaction experiments of SCHINDLER, whereby aden- 

 ine and guanine were converted respectively into hypoxan- 

 thine and xanthine. If this e-xplanation is correct, then 

 adt nine and guanine are- transition-products between the 

 complex proteiel molce ule on the one hand, ami hypoxan- 

 thine and xanthine on the other. These two, in turn, form 

 the connecting link te> the last -step in the- regnssive meta- 

 morphosis of the nitrogenous elements of the tissues, viz., 

 the formation of uric acid and urea. We can thus trae'e a 

 sne-ee'ssion of cycles from the complex nuelein molecule, 

 which is apparently indispensable to the functional aetivity 

 of all reprodue table cells, to the physiole)gically waste pro- 

 ducts urea and urie- aciel. 



S< HII./K and BOSSHARD recently (1886) found in young 

 vi teh, e-Iover, e-rge)t, < te-., a in w base, to which they have 

 given the name vernine. It has the formula C^H^N^Og, 

 and is of especial interest at this point, since on heating 

 with hyelroclileirie aciel it apparently yields guanine. We 

 have, there-lore, at ha-t t\\o \\ell-deline il sou i-e s of guanine, 

 the nne-leinsjind vernine. 



14* 



