He then described their appearance, consistence, and mode of life, advising a simple classification of spheres, rods, filaments or spirals, according to their shape. He further recommended, however, a functional classification, namely, Chromogenic – pigment forming; Septic – Putrefactive; Zymogenic – Fermentative; Pathogenic – producing specific diseases.
 

• Of the Chromogenic, he mentioned, Micrococcus Prodigiosus, a spherical microbe filled with a reddish oil, giving rise to blood-coloured stains upon whatever it might settle e.g., bread, meat, and articles of food. Also the Protococcus Nivalis which in northern regions gives the snow a reddish tinge, and also the Spirillum which renders rain of reddish colour.

 

• Septic or Putrefactive, represented by the Bacterium Termo, which abound everywhere, and are the agents to which all living nature must bear bow, namely, “Dust to Dust.” So soon as life leaves our bodies, they are at once attacked by millions of these microbes, which reduce them to the primary forms from which there were derived, and thus the mineral constituents again mingle with the soil, and so the equilibrium of nature is sustained, there being no creation, no destruction. Plants draw their nutrients from the soil and air in the form of mineral solution, and are devoured by animals; and animals are in their turn devoured by microbes, and return by means of putrefaction to the soil and serve for the nutrition of plants. It has lately been shown that these microbes exist in enormous quantities in the soil to a depth of about 20 inches, but that at greater depths they are comparatively few. This is a factor of great importance to the sanitarian, for it is thus that organized materials such as excreta and refuse of towns, when placed upon the surface of the soil, are quickly changed, whereas, when placed at a greater depth, are slow to undergo decomposition.  It is probably due to the recognition of this fact that thrifty nations such as the Chinese, who use the refuse of their cities upon the soil for agricultural purposes, outlive other nations, such as the Ninevites, Babylonians, Romans and Athenians, who did not recognize this necessity. Thus though, when properly taken advantage of, they are friends to the sanitarian, they are most deadly enemies to the surgeon. Dr Jameson here described how Sir Joseph Lister had discovered a means of contending against them, now known as “Listerism, or the antiseptic system.”

 

• Of the Zymogenic or Fermentative microbe, he mentioned lactic fermentation or the souring of milk due to Bacillum Lactis, the acetic fermentation, or the conversion of alcohol into vinegar, due to Mycoderma Aceti, and also the various diseases of wine, such as mouldiness, over-fermentation, ropiness, and bitterness, all due to microbes.

 

• Of the Pathogenic microbes, which are of such great importance to the physician, he pointed out that it was daily more and more believed that contagious and infectious diseases, such as fevers, are due to microbes multiplying and flourishing in the system. In some such as anthrax and relapsing fever, this has been demonstrated beyond all doubt, and there are many other diseases in connection with which bacteria have been found, e.g. ague, cholera, diptheria, erysipelas, glanders, leprosy, small-pox, typhoid, and tuberculosis or consumption.  He then showed the probable means of combatting these diseases in the near future.

At the conclusion of the address, an interesting discussion took place on the points raised by Dr. Jameson, and before the members separated opportunity was taken to examine under the microscope the specimens of the diptheria and other microbes which Dr. Jameson had provided to illustrate his address.