In certain cases of cystinuria there are found in the urine sulphurized ptomaines, and in measles the urine contains an undetermined ptomaine, _rubedine_, which is very poisonous. _Typhotoxine_, a very toxic ptomaine, has been isolated from the urine of typhoid patients; _erysipeline_, a hardly less toxic base, exists in the urine of erysipelatic subjects; while _spasmotoxine_, _tetanotoxine_, and _tetanine_, exceedingly active alkaloids, are found in the urines of tetanus patients.[11] [11] BRIEGER: Untersuchungen über die Ptomaine, dritten Teil, p. 93; _Berichte d. D. Chem. Gesellschaft_, 1886, p. 3159; 1887, p. 69. As a general rule, all abnormal urines contain toxic bases; the kidneys appear, in fact, to serve as a means of eliminating the toxic products that form in large quantity whenever, and for whatever cause, the organism ceases to functionate normally, whether it be as a whole, or in any one of its parts.[12] [12] CHARRIN: _Les poisons de l'urine_: Encyclopédie Léauté. =Leucomaines.=[13] [13] ARMAND GAUTIER: _Bull. Acad. de Médecin_ (2), XV, p. 115. The leucomaines are basic substances, nearly allied to the ptomaines, but still more closely related to the ureides. They are formed directly or indirectly by the breaking down of protoplasmal albuminoids. The agents that effect the breaking down are the hydrolyzing ferments of the economy. It is well to recall here that these phenomena of hydrolyzation occur within the cell itself and in a practically reducing medium, as we have already stated. The inmost mechanism of these phenomena cannot here be detailed; it will be found described by Armand Gautier in the _Chimie Biologique_, and in his work _Chimie de la Cellule Vivante_.[14] [14] ARMAND GAUTIER: Leçons de chimie biologique. Published by Masson; _Ibid._, Chimie de la cellule vivante. Also published by Masson. The extraction of these bases is an extremely delicate operation. It is necessary to operate with a large quantity of substance, say 50 kilos. The substance is finely chopped, then exhausted with twice its weight of water acidulated with acetic acid (0.2 Cc. per liter) and containing a trace of oil of mustard, which is intended to act as an antiseptic. The albuminoids are precipitated by boiling, the solution then filtered, evaporated in a vacuum at 60° C., and the bases extracted with 95-per cent. alcohol. The alkaloidal bases obtained in this manner are separated by crystallization from alcohol or by various other chemical methods, the description of which we will not enter upon here. In order to facilitate the study of the leucomaines they are classed under three groups, according to their chemical affinities. These groups are as follows: