is not liquefied by them. On potato these bacilli grow like those of glanders, forming a grayish-brown layer on the surface. The comma bacilli thrive best at temperatures between 30° and 40° C., but they are not very sensitive to low temperatures, their growth not being prevented until 17° or 16° C. is reached. In this respect they agree with anthrax bacilli. Koch made an experiment to ascertain whether a very low temperature not merely checked development, but killed them, and subjected the comma bacilli to a temperature of -10° C. They were then completely frozen, but yet retained vitality, growing in gelatine afterward. Other experiments, by excluding air from the gelatine cultures, or placing them under an exhausted bell-jar, or in an atmosphere of carbonic acid, went to prove that they required air and oxygen for their growth; but the deprivation did not kill them, since on removing them from these conditions they again began to grow. The growth of these bacilli is exceptionally rapid, quickly attaining its height, and after a brief stationary period as quickly terminating. The dying bacilli lose their shape, sometimes appearing shriveled, sometimes swollen, and then staining very slightly or not at all. The special features of their vegetation are best seen when substances which also contain other forms of bacteria are taken, _e. g._, the intestinal contents or choleraic evacuations mixed with moistened earth or linen and kept damp. A most important statement was that the comma bacillus seems to be killed by the bacteria of putrefaction, and consequently agents that destroy the latter organisms without the former may really do injury, by removing from the cholera bacillus an impediment to its growth. As for destructive agents to the bacillus, he found it killed by solutions in the following proportions: oil of peppermint, 1 in 2,000; sulphate of copper, 1 in 2,500 (a remedy much employed, but how much would really be needed merely to hinder the growth of the bacilli in the intestine!); quinine, 1 in 5,000; and sublimate, 1 in 100,000. In contrast with the foregoing measure for preventing the growth of these bacilli is the striking fact that they are readily killed by drying. This fact is proved by merely drying a small drop of material containing the bacilli on a cover glass, and then placing this over some of the fluid on a glass slide. With anthrax bacilli vitality is retained for nearly a week; whereas, the comma bacillus appears to be killed in a very short time. Dr. Koch having found and cultivated the comma bacillus and ascertained its distinctive character, next proceeded to investigate its relation to cholera. In all there were now about one hundred cases of cholera in which the bacillus had been found, while it was never found in connection with other diseases. Three different views, said the speaker, as to its relation to the cholera process are tenable: