12 Ibid., p. 14.
Cruveilhier (1829), admitting the doctrine of the formation of secondary abscesses being due to capillary phlebitis, further laid down an axiom, since proved untenable, that the foreign body introduced into the veins, whose elimination by the emunctories is impossible, will produce visceral abscesses similar to those which occur after wounds and operations, and that these abscesses are the result of capillary phlebitis of those viscera.13
13 Braidwood on Pyæmia, p. 14 et seq.
During the early part of the present century it was generally admitted by the best authorities that the symptoms and lesions in pyæmia were entirely due to the presence of pus in the blood, but whether absorbed from the wound or developed by an inflammation of the veins was at that time a disputed question.
Haller made the first experiments on animals with putrefying substances in the latter part of the eighteenth century, and was convinced that nothing destroys the animal fluids more powerfully than putrefaction. Gaspard (1822) published a complete work based upon his experimental research in regard to the action of putrefying substances on living organisms. He, having produced septic infection in animals by injecting into their blood pus or other putrefying substances, thus prepared the way for other experimenters, by whom he was quickly followed. Ernst R. Virchow repeated the experiments of Gaspard, and discriminated with greater precision between the surgical diseases—septicæmia with its sharply-defined group of symptoms, the opposite of pyæmia. Furthermore, "he showed that the changes in the veins which had been regarded as due to phlebitis were caused by the coagulation of the blood and by subsequent degenerative changes in the thrombi thus formed; that the infarctions and abscesses seen in the viscera were due to emboli which had become detached from softened thrombi; that, as the white blood-globules and pus-globules were identical in appearance, they could not be distinguished; and that it was improbable that pus-globules made their way into the blood."14
14 The International Encyclopædia of Surgery, ed. by Ashhurst, vol. i. p. 204.
Panum (1855) conducted a series of important experiments, and endeavored to separate the infectious substance and determine its real nature. He concludes that the real poison is not identical with any of the chemical combinations or any of the single substances which have until now been isolated by chemical analysis from the products of nitrogenous decomposition, but adds that it is probably a concealed ferment belonging to the so-called extractive matters—carbonate of ammonium, leucin, tyrosin, fatty acids, acetic acid, etc. Furthermore, that the putrid poison is stable, fixed, and non-volatile; that it is neither decomposed by boiling nor by evaporation to dryness; that it is insoluble in absolute alcohol, but soluble in water; that the albuminous substances found in putrefying liquids become venomous only because they are impregnated with the septic poison; and that washing these substances in a large quantity of water renders them innocuous; and that the energy of these putrid poisons can only be compared to the venom of serpents, curare, and other vegetable alkaloids.
The prize offered by the Faculty of Medicine at Munich for the best essay on the action of putrefying substances in the animal organism was awarded to Hemmer in 1866. His essay was distinguished for its accurate delineation of the pertaining literature and for the number of experiments reported, while his conclusions bear a striking resemblance to those of Panum.
Bergmann in 1868 sought to determine the poisonous element contained in decomposing animal substances, and for this purpose chemically treated putrid fluids, hoping to find the agent that would excite all symptoms of septic poisoning. He obtained a body of this nature from decomposing yeast, which he called sepsin, although we have no proof that either he or any one else has ever found the same in pus or any decomposing animal matters; and even if it had been found in these, it would then become necessary to demonstrate the fact that no other substance contained in the putrefying liquids could produce septic poisoning. Many other experiments, similar to those which have just been mentioned, were made in the mean while by Magendie, Stich, Billroth and Hufschmidt, O. Weber, Duprey, Learet, Urfrey, Saltzman, Fischer, Frese, Muller, and others. Bergmann had extracted the sepsin from yeast, but Schmidt and Petersen (1869) were able to obtain it from putrefied blood. In 1869, Zuelzer and Sonnenschein claimed, on the contrary, to have separated a new, unnamed septic alkaloid, which was not the sepsin, and the action of which resembled that of atropine and hyoscyamine. Nevertheless, the separation of the sepsin or of the alkaloid of Zuelzer seemed to demand a talent in the manipulator which is not possessed by everybody, and rare are the chemists who possess it—so rare that these substances are not yet either officinally recognized or classified. The attention of the medical profession had now become thoroughly fixed on the chemical character and the physiological action of these newly-discovered substances. It is therefore only natural that we should find during the next few months that the medical societies were much occupied with discussions on these subjects, although no important progress seems to have been made.
Political events now gave a new direction to thought, and the Franco-Prussian War filled the hospitals of both nations with wounded in which there was opened a grand field for the practical study of purulent infection in all its various forms. Humanity now demanded the best efforts of the medical profession. Neither the mechanical nor chemical theories had ever yielded practically any beneficial results; consequently, something better was demanded in this emergency. It was during this important epoch that the germ theory began to assume form and to attract some general attention in the medical profession, although Schroeder and Dusch had shown in 1854 that the filtration of the air through cotton was sufficient to prevent the putrefaction of albuminous substances which had been previously boiled. Pasteur also demonstrated the existence of germs in the air in 1863, and likewise showed their agency in the process of fermentation.