It has been generally accepted that petroleum has originated from animal and plant remains--particularly from fats, oils, waxes, and resins--these substances being relatively resistant to decay. However, they are readily hydrolyzed in nature into their components, that is, fatty acids and an alcohol, especially glycerol. The course of decomposition of glycerol is well known, but of the fatty acids, the decomposition of acetic acid only has been extensively studied. It is decomposed under anaerobic conditions by the methane bacteria to carbon dioxide and methane.

In the present paper the writer is concerned with the hypothesis that the higher homologues of the series might be decomposed by the same group of bacteria to carbon dioxide and the corresponding hydrocarbon. Results of experiments show that this is not the fact, but that all the fatty acids studied, from acetic to margaric, give rise to carbon dioxide and methane only.