Heteroxanthine, C₆H₆N₄O₃.—From urine.
Methylxanthine, C₆H₆N₄O₂.—From urine.
Paraxanthine, C₇H₈N₄O₂.—From urine—destroys spontaneous muscular action, lessens reflex excitability.
Carnine, C₇H₈N₄O₃.—From fresh meat.
Gerotine, C₅H₁₄N₂.—From liver and kidneys, an isomer of cadaverine—exerts a paralysing action upon the nerve centres and cardiac ganglia.
Spermin, C₂H₅N.—From semen, testicles, ovaries, breast, thyroid, pancreas, and spleen, normal bone marrow. Poehl states that it has a tonic effect on the nervous system.
Creatinine, C₄H₇N₃O.—From urine.
Crusocreatinine, C₅H₈N₄O.—From fresh meat.
Xanthocreatinine, C₅H₁₀N₄O.—From fresh meat—causes depression, fatigue, somnolence, defæcation, and vomiting.
Betaine, C₅H₁₁NO₂.—From urine.