Hemialbumose, from which peptones are formed, is itself a dangerous toxin. It is generally believed that the toxic action of the peptones and of the products of digestion of the albuminoids is due not to the peptone itself, but to the more advanced products of digestion, alkaloidal products unquestionably closely allied to the ptomaines. Nevertheless, the true peptones behave just like true poisons, when they are introduced hypodermically into the blood.[72] [72] SCHMIDT: _Mühlheim, Arch. de physiol._, 1880. Brieger has made us acquainted with a non-proteid substance, under the name of "peptotoxin," which is met with at the beginning of the putrefaction of albuminoids. This toxin, which is not a protein, is nothing else but a ptomaine. It is not altered by heat, and possesses a very high toxicity. Brieger claims that it is a hydroxylized derivative of an aromatic amide.[73] [73] BRIEGER: _Berichte d. D. chem. Gesellsch._, XIX, p. 3120; and _Verhandl. d. Congress f. innere Med._, II, p. 277. Besides these facts, experiment has shown that the leucocytes, or white corpuscles, the defensive rôle of which we have noted in phagocytosis, owe their properties to the ferments which they secrete, and particularly to some of the digestive ferments. These white corpuscles are very rich in ferments of all kinds. Rossbach found in them amylase; Achalme found lipase, casease, and trypsin; and the study of immunity has brought to light a series of other ferments, the alexins or cytases (microcytase and macrocytase), which have an exceedingly important rôle to play. It may easily be conceived that under certain circumstances a part or the whole of these ferments can pass into the blood of the fluids of the body, when they give rise to serious disturbances in certain cases, or confer immunity in others. It is thus that, according to Gautier, the rise of temperature which characterizes fever is a consequence of the abnormal transudation of these normal ferments into the blood, and their transmission by the general circulation to the nervous centers. However, it is not only in the leucocytes that we meet with these toxic digestive ferments; it appears quite probable, and has even been partially demonstrated, that they occur in a large number of other cellular elements. It is not necessary here to dwell upon the formation of the antibodies of this group of active substances. The animal toxins are animal diastases, and we have seen in the preceding paragraph that these substances yield specific antibodies with great facility. For the rest, we will dwell more fully on these antibodies of the animal toxins in another volume of this collection, specially devoted to the study of these substances, and entitled "_Les Serums Immunisants_," to which we refer the reader who is desirous of obtaining more complete details than he can obtain in the present volume.