19 In some instances in which absorption from the tissues is very rapid the effects of subcutaneous injections may be similar to those produced by injections made directly into the circulation, and the local lesion be insignificant.
This capacity of self-multiplication which septic fluids possess has recently been found to be coincident with the presence of certain parasitic bodies, generically termed bacteria. All carefully-made experiments serve to show that if a septic fluid be deprived of these organic bodies by boiling or filtration while it continues capable of producing inflammation, the inflammation is usually of diminished intensity and remains local in its character;20 whereas the bacteria retained upon the filter possess all the virulent properties of the original fluid.21 This does not alone necessarily prove that the virus resides in the bacteria, for it does not exclude the possibility that both the virus and the bacteria remain upon the filter.
20 In filtration through porous earthenware cylinders the filtrate possesses no phlogogenic properties.
21 Tiegel, Correspondenzblatt für Schweizer Aertze, 1871, S. 1275; Klebs, Archiv für exp. Pathol. und Pharmakol., Bd. i. Heft. 1, S. 35.
So far, attempts at isolating the microspores of septicæmia and cultivating them separately in vehicles composed of water holding in solution inorganic constituents, or sterilized fluids containing organic matters, or of the semi-solid gelatinous substances recommended by Koch, have been only partially successful in proving them to be the sole source of infection. Some earlier experiments of Tiegel and Klebs22 were attended with positive results, and more recently confirmatory evidence has been furnished by Pasteur and Doléris.23 Hiller, rarely quoted now, arrived at different conclusions. He found that bacteria washed in pure water were innocuous.24 But pure water had long before been proven by observers to be inimical to the well-being of the organisms in question. Schüller says that Hiller's experiments prove apparently that while a putrid fluid may be in the highest degree poisonous, its component parts—viz. either the fluid or the bacteria singly—are neither deadly nor poisonous.25 The fact is, that isolation experiments are subject to what has hitherto been in most experiments an unavoidable source of error. As Davaine noted early in his observations, the physiological action of bacteria is very dependent on the constitution of the medium in which they are developed, which is in entire harmony with what is known of organisms much higher in the scale. "Many plants," says Burdon-Sanderson,26 "containing active principles, become inert when transplanted from an appropriate soil." Bucholtz, in a series of experiments designed to test the influence of antiseptics upon the vitality of bacteria, found not only a difference between those taken directly from the infusion and those cultivated in artificial fluids, but between bacteria derived from the same source and cultivated in modifications of the nutrient medium.27 Then, too, it is not always safe to transfer to the human species the results of experiments made upon the lower animals. Indeed, among animals, not only in different species, but in varieties of the same species, differences in the susceptibility to septicæmic poisons are found ranging from gradations as to the intensity of the effect produced to absolute immunity. In anthrax, a disease analogous to the one in question, the bacterial origin has been established beyond dispute by the inoculation of isolated bacilli, which multiply in the blood and permeate in enormous numbers the lungs, liver, kidneys, spleen, and glandular structures. If the same unequivocal testimony has as yet not been obtained from isolation experiments as regards septicæmia, it is reasonable to suppose that this is due to the defects in the technique, for which it is presumable the ingenuity of investigators will in future find the remedy.
22 Archiv für exp. Pathologie und Pharmakologie, "Beiträge zur Kenntniss der Pathogenen Schistomyceten," Band iv. Heft 3, S. 241 und ff.; Tiegel, loc. cit.
23 In this connection may be mentioned some very interesting experiments by Dr. George Gaffky (Experimentellen Erzengte Septicæmie, Mittheilungen aus den Kaiserlich, Gesundh. Amte), in which micrococci from the blood of septicæmic mice were successfully cultivated in a gelatine preparation, and produced, when inoculated in small quantities, the symptoms identical with those obtained by inoculating the blood itself.
24 "Exp. Beiträge zur Lehre von der organisirte Natur der Contagion und von der Faülniss," Archiv für klinische Chirurgie, Bd. xvii. Heft 4, S. 669 u. ff.
25 "Exp. Beiträge zum Studium der septischen Infection," Deutsche Zeitschrift für Chirurgie, Bd. vi. S. 162.
26 "Lectures on the Relations of Bacteria to Disease," British Med. Journal, March 27, 1875. See also Klebs, "Beiträge zur Kenntniss der Pathogenen Schistomyceten," Arch. für Pathol. und Pharmakol., Bd. iii. S. 321.