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Transactions. 13 
These microscopic germs were arranged in a class by themselves 
under the name Schizomycetes, or splitting fungi, and were placed 
between the alge on the one side and moulds on the other. They 
were divided into four principal groups, viz.—micrococet, bacteria, 
bacilli, and vibrios and spiral microbes ; but this like all other 
classification, was only a matter of convenience, for in appear- 
ance they closely resemble each other, and the dangerous ones— 
pathogenic—can scarcely be distinguished from the septic or 
perfectly harmless ones. Having described several of the germs 
and exhibited microscopic drawings of a number of them, he 
referred to the multifarious modes by which infection can be 
spread—by direct contagion, by infectious matter from diseased 
persons escaping from sewers, &c., being introduced into water, 
foods, or articles used for culinary purposes, and by the inhilation 
of vitiated air. He believed that before the disease was propa- 
gated there must be certain conditions favourable to the growth 
and development of the germ. For example, if seed were sown 
on a macadamised road it would not grow for want of sufficient 
nourishment ; but if in a cultivated field, it would have all the 
conditions favourable to its growth. In the case then of the germs 
of disease, they must have the suitable nidus or else perish. 
There are other conditions governing the spread of disease, such 
as predisposition through weakness or other causes. Although 
the germs of the different diseases have some things in common, 
they do not always attack the system in the same manner, for 
each disease has its own characteristic. The germ of diphtheria 
(micrococcus diphtheriticus) attacked the throat, while those of 
cholera and typhoid fever attacked the alimentary canal. 
Tn reference to their cure, the well-known axiom, “prevention is 
better than cure,” was all that he would then offer, but as to 
how “to prevent” the disease he said—Ist. Limit the sphere of 
action by complete isolation of the diseased; 2nd. Fresh air, and 
plenty of it; 3d. Thorough disinfection. Having described a 
number of experiments made with disinfectants, he recommended 
chloride of lime as the cheapest and one of the best, but it had a 
disagreeable odour, and was detrimental to colours, &e. Solu- 
tions of permanganate of potassium were good, and could be 
easily used, also carbolic acid, and the various powders contain- 
ing it, and sulphur and sulphurous fumes. One of the best was 
a solution of mercuric chloride, but this was a deadly poison, and 
he did not recommend it for that reason. In conclusion, Mr 
