308 BACTERIAL POISONS. 



in from six to twenty-four hours, and produce increased re- 

 flex excitability and convulsive attacks ; 5-100 mg. is fatal 

 (Filehne). When injected subcutaneously into hepato- 

 tomized geese or chickens a corresponding increase in uric 

 acid secretion is observed (v. Mach). This conversion is 

 analogous to that observed by Stadthagen in the case of 

 guanine (page 310), and shows that in the xanthine bodies 

 we have antecedents of uric acid apart from the synthesis of 

 the latter from ammonia in the liver. The process by which 

 this change is efibcted is undoubtedly one of oxidation. 



GxTANiKE, C5H5N5O, was discovered, in 1844, by Unger, 

 as a constituent of guano, in which it is present in varying 

 quantities according to the region from which the guano 

 comes. Thus, the Peruvian guano is reported as containing 

 the largest proportion of this base, and on that account this 

 variety is employed when it is desired to prepare guanine. 

 Since its discovery by Ungee, it has been met with in a 

 very large number of tissues, both animal and vegetable ; 

 in the liver, pancreas, lungs, retina, in the thymus gland of 

 the calf, and in the testicle substance of the bull ; in the 

 scales of the bleak, and in the swimming-bladder of fish, as 

 well as in the excrements of birds, of insects, as the garden 

 spider, in which it occurs with a small quantity of uric acid 

 (Weinmans), and is to be regarded as a decomposition 

 product of proteids formed in the tissues of the spider. It 

 is also found in the spawn and testicle of salmon, and 

 ScHULZE and others have shown it to be present in the 

 young leaves of the plane-tree, of vine, etc., also in grass, 

 clover, oats, as well as in the pollen of various plants. 

 ScHtJTZENBEEGER has isolated it, together with hypoxan- 

 thine, xanthine, and carnine, from yeast which had been 

 allowed to stand in contact with water at near the body- 

 temperature. Pathologically, it occurs in the muscles, liga- 

 ments, and joints of swine suffering from the disease known 

 as guanine-gout. Normally, guanine, like adenine, is 

 present in muscle tissue only in traces. It has never been 

 found in the urine, though xanthine has been mistaken for 

 guanine by some. 



