periments he drew the conclusion that the virus of putrid infection is not an organized ferment, not bacteria, but an albuminoid substance. Panum, who held similar views twenty years ago, has reasserted his belief in them in an article published in Virchow's Archives, for July, 1874, and during the last year the weight of testimony has all been in this direction. Clinical observation has been employed to confirm or refute the conclusions of experimental pathology, and has clearly demonstrated that the poisonous processes, of which we have spoken, can begin in the human body and proceed without the presence of bacteria, and that bacteria may be present in large quantities without the slightest symptom of any poisonous complication.
Fig. 4.—Torulæ.—From a Solution of Ammonia Tartrate and Sodic Phosphate.
It is probable that their rôle, so far as disease is concerned, is as follows: While they have no power in themselves to excite disease (diphtheria, vaccinia, septicæmia, typhoid fever, etc.), they are able to absorb the poison (ferment?) which is capable of producing it, to "fix" it, as it is termed, and to give it up to any tissue with which they may come into contact, acting thus as carriers of contagion; then, after the abnormal process has been commenced in the body, a change is brought about in the tissues which renders them suitable for the rapid growth and multiplication of the bacteria, which, in turn, augment the change in the tissues, and thus there is formed a vicious circle, the consequences of which are too often fatal.
Any agent which destroys the life of the bacteria, or prevents their multiplication, breaks this circle and renders a cure possible.
The influence of bacteria in fermentation is still undecided, but, for the sake of completeness, the different opinions should be mentioned. It is admitted by all chemists that these or similar organisms are invariably present in some fermentations—Bacterium termo, or rod bacterium, in putrefaction, and the yeast-plant in alcoholic fermentation, for example; and while some claim that the process is due to the vitality and growth of these plants, others hold that this growth is an effect, not, a cause; and a third party claim that the plants secrete the actual ferment.
According to Liebig, fermentation is an action which is produced in a fermentable substance by an albuminous matter which is dead and in spontaneous decomposition; that is, fermentation is a correlative phenomenon of death. On the other hand, Pasteur maintains
