"The one precaution to be observed in bacteria cultivation is to thoroughly sterilize all vessels and instruments used in the promotion of the culture. This is effected either by a dry heat of 160° Centigrade, or a vapor heat of 100° Centigrade. The former is on all accounts the more satisfactory, although some-what destructive to the fine tempering of steel instruments.

...re-agent glasses. These are prepared by first cleaning them and then closing their openings with wads of cotton. The process of sterilization is the same as that employed in other vessels, but the cotton-wadding, by turning slightly brown, enables one to tell very nicely when the glass is sterilized."

~ Ten Days in the Laboratory with Dr. Robert Koch, of Berlin

"Prof. Koch first commenced experiments with a tube which we represent. It is an ordinary test tube, such as is used in all ordinary experiments. It is, in the first place, sterilized over the fire, then a bouillon of sterilized culture is poured into it, that is to say, culture which does not contain any germ."

~ Rober~ Koch's Discovery - (Illustrated): Alimentation as a Therapeutic Measuret Heinlein

"...the microbe, which is taken directly from the mucus of a consumptive, is placed in the tube and orifice is closed with cotton, thereby permitting the air to pass into the vessel, but retaining the organisms, which are heald suspended therein. The tube thus prepared is subjected to an even temperature in an oven. After a certain length of time the microbes begin to develop and increase, and assume the clotted appearance which we in one of the engravings, and which is one of the characteristic peculiarities of consumption. ...take some of that treated as above and place it in another tube. This is repeated, and after fifty or sixty successive changes of this nature a residuum is obtained which is called pure culture, that is to say, it contains absolutely nothing but the microbe which it is desire to study."

~ Koch's Discovery - (Illustrated): Alimentation as a Therapeutic Measure

"The method itself is so easily understood that a physician possessing an ordinary knowledge of microscopical research would have little difficulty in cultivating, in the pure state, and bacillus with which he may be especially interested, and in a comparatively short time..."

~ Ten Days in the Laboratory with Dr. Robert Koch, of Berlin

"To cite the best known of these, we will take the bacillus anthracis... This bacillus occurs in certain marshy districts of Europe... and causes the endemic appearance in the cattle inhabiting these parts of the splenic fever disease. Koch has discovered that the plant grows as well outside of the body, in a suitable medium... He found that the bacillus grows best in an alkaline vegetable infusion. ...vegetable infusions are acid in reaction, but these infected localities it has been found that owing to lime in the soil they are alkaline and hence afford the desired reaction for the best propagation of the plant. Cattle, by grazing in these districts, become infected with the spores through abrasions on the lips, tongue, etc; or, as Koch has also shown, the spores develop in the alkaline fluids of the intestinal canal into the perfect bacilli, which the penetrate the walls and thus gain entrance to the circulation

~ The Germ Theory of Disease by Walter Mendelson