NOTES AND MEMORANDA. 
Dr. Koch’s New Method of Pure Cultivation of Bacteria.—At 
the recent meeting of the International Medical. Congress in 
London, during August, Dr. Koch, well known by his 
researches on the life-history of Bacillus anthracis (see this 
Journal, Vol. XVII, p. 87), gave a series of demonstrations 
in the physiological laboratory of King’s College, which 
were of the greatest interest and importance. 
Dr. Koch has recently been appointed to the charge of a 
laboratory of experimental research connected with the State 
Department of Public Health in Berlin, and aided by his 
two assistants, he brought to London material and instru- 
ments for the purpose of exhibiting to the members of the 
Congress the methods of research into the relation of Bac- 
teria to disease, devised by him. The series of photographs 
of various forms of Bacteria shown by Dr. Koch were valu- 
able, as affording convincing evidence of the necessity of 
making use of photography as the means of obtaining and 
preserving a record of the specific form and character of 
Bacterian growths. Of great interest also were the cultiva- 
tions of the Bacteria of blue milk, and of those of blue pus, 
exhibited by Dr. Koch, and of the septic Bacterium of 
putrid blood, the toxic effects of which were experimentally 
demonstrated. 
Of most general importance, and in our judgment likely 
to mark altogether a new era in the study of the relations 
of Bacteria to certain diseases, and to other fermentative 
processes, was the demonstration by Dr. Koch of a new 
and yet absolutely simple and obvious method of obtaining 
pure cultivations of the species of Bacteria. 
It is a well-known fact that there are a large number of 
species of Bacteria differing from one another in the effects 
which they produce in the medium wherein they are culti- 
vated. It is also well known that Bacteria are so ubiqui- 
tous that the examination of any natural medium attacked 
