487
In some spaces, the cells showed evidence of degeneration This was mostly of a fatty nature. In other parts of the tumour, the spaces contained, in addition to the cells, blood-the result of small hæmorrhages from the surrounding vascular
stroma.
It is evident, therefore, that the variegated appearance of the cut surface of the tumour was owing to the presence of these islands of cells, their pigmentation and varying degrees of degeneration and to the occasional occurrence of small hæmorrhagic extravasations.
Remarks: It is difficult to come to a conclusion as to the real pathologi- cal nature of this new growth. The youngest parts of the tumour contain cells which morphologically are similar to those found in the cortex of the supra-renal capsule. Their polygonal shape, their contained piginent, and the method of form- ing a tissue, all tend towards such a conclusion.
No giant cells could be found in sections of the growth.
Again, the tumour did not present any of the characteristics described by MARCHAND and others, as occurring in growths from the medullary portion of the capsule.
Taking all the points before me into consideration, I conclude that, in this case, I am dealing with tumour of the adrenal, of progressive growth, and malig- nant characteristics, the cell type being closely allied to cortical supra-renal gland tissue.
Plague.
Number of cases examined-312.
During the past year, a special report was presented to the Government deal- ing with my researches into this disease, from an epidemic and epizootic point of view. The relations, existing between the different types of plague, were fully discussed, and, for a number of reasons, plague was regarded as a septica nic disease ab initio. The avenues of infection in plague were found to be chiefly the alimentary canal and the skin. Again, it is probable that many cases of plague occur through infected food. Plague bacilli have been found in the cheapest and most inferior quality of rice; rats fed with this rice contracte i the disease. Further, nutrient media prepared from rice form suitable soil for the growth of the B. pestis. The spread of plague by insects can only be occasioned indirectly by infect- ing food, etc.
I endeavoured as far as possible to show the relation existing between humaan and rat plague. Charts were prepared showing the incidence of epidemic and rat epizootic plague, and froin then it is evident that some close relation exists be- tween the two varieties of the disease. Generally speaking, human plague appeared about a week to a fortnight later than rat plague. The appearance of a rat plague epizootic was proved conclusively to be followed by a plague epidemic.
The most important prophylactic plague measure is, in my opinion, a whole- sale destruction of the rats.
During the past year, much fewer cases of the disease have been examined.
The number of rats examined has also greatly diminished. This is disappoint- ing. It may be partly accounted for by the stricter measures adopted by the Sanitary Board for the collection of rats. It cannot be said that the rodent is be- coming scarce in Hongkong.
It is proposed to use Danysz's virus for the destruction of rats. During the early part of 1904, an attempt was made to prepare this virus with cultures of the organism which I brought with me from England, and some which I received from Professor SIMPSON. They were vaineless, however, and it was found im- possible to recover their virulence.
Fresh strains of the virus have been ordered from Professor Roux of the Pasteur Institute in Paris, and it is hoped that results, similar to those obtained in certain parts of France, will be had in Hongkong.