(INIMICAL BASIS OF THE ANIMAL BODY. 181 



isolated nucleiu yields no inconsiderable amount of hypoxanthin. 1 

 'I'll'- nuclein huwever from egg-yolk does not yield hypoxanthin. 

 and thus resembles the nuclein derivable from ca-ein.- Although 

 the xanthin-bases undoubtedly result in the body from tin- meta- 

 bolism .if iiitr.^.-nous (proteid) tissues there is as yet no evidence as 

 to the manner in which they can be formed from true proteids. 8 

 Tin- urn. -tic relationship of hypoxanthin to nuclein probably ac- 

 counts for the marked occurrence of the former in leukhaemic 

 blood. 



Bearing in mind the close chemical relationship of uric acid, 

 xanthin, and hypoxanthin, and regarding the xanthin ba.-> 

 distinctly and typically products of the downward metabolism 

 of nitrogenous ti>sues, the i|iiestion at once suggests it.-elf 

 whether in the body there is any anteeedental relationship be- 

 tween these substances and uric acid or urea . As with kreatin 

 (above, p. 162), so with the xanthin bodies, the disproportion 

 between the amount presumably arising in the tissues and that 

 which is actually excreted makes it probable that they are con- 

 mething else, uric acid (or urea), before leaving the 

 body. And in support of this belief there is a certain amount 

 of experimental evidence which was wanting in the case of 

 kreatin. It is found that hypoxanthin administered to a dug 

 does not reappear as such externally in the urine, 4 and that when 

 given to fowls it leads to an increased excretion of uric acid 

 amounting to some 60 p. c. of the hypoxanthin employed.' 1 Since 

 the latter iv-ult is obtained in fowls with extirpated livers, it ap- 

 that the coii\cr>ion is not effected in this oigan, although it 

 is known that normally no inconsiderable portion of the uric acid 

 i> formed in their liver. 



<;. Adenin. C,H,N 



This base was obtained by Kossel * during the treatment of 



pancreatic ti>-ue for the preparation of hypoxanthin. It bears 

 the >ame relationship to the latter that guanin <lo,.> to xanthin. 

 ami can similarly be convert,-.! into hypoxanthin by the action of 

 nitrous acid. It is stated to have been found in urine." 



1 'A f. ;./-/>//. Ch,,n. H.I.-. 111. (1>7'.M. S. _'-i. \\ J'.Hi. \ i:,i'. (-. v i. -j:;. vn 7 

 ''.LIST'S Arch. H.I. xxn 



ndi <l. i.hytiol. Geiell.. I / . I8C 



./. d. chem. Gesell. 188(i. -- MO Hut tux also Salomon, //./. 

 8. IK 



4 I'.a^il.sky, Zf. f. },h,,nol. Chrm. H.I Mil (]v-t). S. 397. 



. M.i.-li. -In/., f. fij>. l',itl>. ii. /'/Kin,,. I!.!.- \\iii (1SS7), S. U.. 



ilso RtadtliM ' l,.-i.,w. 



I. d. /!. G'..s- /. is-:,. M, ; t\ ) >hi l iiol. Chem. Bde. X. |i 



MI. (1888), S. '.'41. \M (18M > I S-liimllrr .//"./ . MM 



.) ilir-< tii. us fur .-|.:ir:it i"ii <>f xanthin, hvfioxanthin. cnanin. an<i 

 a.li-nin. Thuiss, //-/</. H.I. MIL > 898 I'.rnh. 

 ir.T. I' id. H.I. x\i 160 



St;i.lth;if:i-n. Vin-h-... - 390. 



