It is a well-known fact that more or less gas producing bacteria are present in almost all ordinary milk. The number present varies with the season of the year and the treatment the milk has received.
Proceedings of the Iowa Academy of Sciences
©1900 Iowa Academy of Science, Inc.
Eckles, C. H.
"A Method of Isolating and Counting Gas Producing Bacteria in Milk,"
Proceedings of the Iowa Academy of Science, 8(1), 144-145.
Available at: https://scholarworks.uni.edu/pias/vol8/iss1/22