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All foods in the natural condition coutain many species of micro-organisms. The majority of these are harmless non-pathogenic germs. They consist mostly of cocci and bacteria, accompanied by moulds of several species. My result in regard to the general bacteriology of foods is in harmony with those obtained by other observers. My object, however, in carrying out this research, being the determination of the presence or absence of the plague virus in foods, special attention was paid to the latter. My research was crowned with success by the discovery of plague bacilli in considerable numbers in rice. Repeated examination of this food was made. and the result was always positive. The rice fiend infected was the cheapest and most inferior quality of the cereal. This quality is used as food by the majority of the poorer class of Chinese. If reference be made to the attached table it will be found that the samples Nos. 6 and 7 were contaminated with the B. pestis. There was no doubt about the micro-organism. Its presence was confirmed by experiments on rats.

Sample No. 15 must be regarded as suspicious. Micro-organisms, morpho- logically and biologically like the B. pestis, were found. The results of experiment were negative. 'ne is not justified, however, in declaring such a sample to be plague infected in the absence of positive experimental evidence.

Rice is the only food which I found infected. Further investigation would probably have led to other positive results, but the extension of the enquiry was inipossible at the time. The discovery of the plague bacillus in food is not new. GLADIN (Cent. f. Bakt. Bl. 24, 1898) kept the B. pestis alive for more than three weeks in milk, albumin, potatoes, plums, apples, bread, etc. This is of great importance, in my opinion, if we consider the large quantity of fruit consumed in raic state by the natives and Europeans in Hongkong. The question of the presence of infected fruit in our local markets, and the frequent consumption of fruit in the market by Europeans and natives alike must not be forgotten in tracing the sources of plague infection.

Again, the results of STADLER (Arch. f. Hygiene Bd. 35, 1889) are interesting. This observer found plague bacilli alive and virulent in pickled flesh, even after the process of pickling had been carried out for 16 days. So far as Hongkong is concerned this is important. It is known that pork is the chief meat of the Chinese in the south, so much so that the word meat is often used to mean pork. Further it is probable that the pickling or salting as done by the Chinese is not carried out in a scientific manner or without the admixture of a considerable amount of extraneous dirt.

The results obtained by HANKIN (Das Österr, Sanitätswesen, 1897) are similar to those obtained by myself. This investigator found that the length of life of the plague bacillus on gram was considerable.

Food as an important vehicle for the conveyance of infection, has been re- cognised for some considerable time. To show its importance in disease, it is only necessary to mention Typhoid fever, Cholera and Botulism.

Foods become infected with bacteria in several ways.

may

(1.) Saprophytes are normally present in the food. Under ordinary condi- tions they are harmless. Occasionally, however, they take on a rapid growth, resulting in the production of considerable quantities of poisonous matter which excites disease. A good example is the presence of FLÜGGE'S peptonising bacteria in milk (Zeit. f. Hyg. Bd. 17, 1895).

(2.) Pathogenic bacteria may be conveyed to man through flesh or fluids obtained from sick animals. A well known example is tuberculosis. Such a thing has been proved to occur in experimental plague. It is easy to intect al- most any animal by feeding it with pieces of plague infected human spleens or blood. There is no reason to doubt the reverse of this experiment.

(3.) The causal agents of the most important infectious diseases in man fre- quently reach the food.

These agents are conveyed to the food by man himself and also by animals. By man owing to his carelessness and filthy nabits-and this is probably a factor of great importance amongst the Chinese; by animals such as rats, mice, cockroaches, flies, etc., which either by contact or by the infected condition of their secretions and excretions, deposit the specific germs on the article of diet.