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(a) The examination of the blood on reception of the patients into hospital was the first object for attention as the most easily procurable material for the diagnosis of doubtful cases. By the microscope alone I detected the bacillus in the blood in 32 cases out of 45 examined, ¿e., 71 %. Cultivation of the blood on gelatine and agar agar gave 29 positive results out of 35 cases, and G cultivations were negative. This gives 83 % with positive results by cultivation. Of the first 32 patients 26 died, whilst of the latter 29 cases 25 died. These numbers show that one is able to find the bacillus in the great majority of severe cases in the early stage by careful microscopic examination, whilst still 10% more can be recognised by cultivation experiments. In one case streptococci were found besides,
(b) Examination of discharge from newly opened buboes and abscesses showed in all cases examined the presence of the plague bacillus. In about half the number of cases streptococci and staphylococci were found besides. The number of the bacilli generally correspond to the advancement of the swelling and destruction of the gland.
(c) The sputum of 12 plague patients suffering from bronchitis showed 11 positive results on cultivation. one cultivation was negative.
(d) In two cases of cultivation from the fur on the tongue the plague bacillus developed on gelatine.
(e) The culture examination of forces gave positive results in all of the 15 cases examined where well marked enteric symptoms were present. In 8 of these cases no externally apparent bubo was present.
(f) After post mortem examination the various internal organs were frequently examined, and in all cases the tissue of the spleen and in most cases the liver, the mucous membrane of the stomach and intestine, and the lungs gave positive results by culture and subsequent animal experiments.
All these examinations were made carefully and the positive results are beyond any doubt, and as they were made with imperfect apparatus the further experiments will prove more than this. I hope to be able to state whether or not the bacillus is present in the soil of the Colony at different places, in the dirt of infected houses, in the water and latrines, clothes of infected persons, &c.
I will now report shortly about the inoculations performed on different animals. Two pigs, three monkeys, one car. six rabbits, seventeen guinea-pigs and three mice were operated on, The inoculated substances were diseased tissue and pure cultures-two spleen inoculations, seven gland inoculations, two inoculations of the fur of the tongue, one blood culture, two pus cultures, eight fœcal cultures, four sputum cultures. Four guinea-pigs and two monkeys died from plague without being inoculated.
Of eighteen animal inoculations in the abdomen seventeen gave positive results, that is to say, the animals died of plague. Implantation of diseased tissue and pure cultures into the stomach by feeding or introducing them into the œsophagus by glass tube was made in nine cases with five positive results. These cases died showing clinical and anatomical symptoms of plague whilst under observation and on the post mortem table. The other ones-two rabbits, one cat and one guinea pig-were sick for a week, showed irregular fever but recovered. The one case of subcutaneous inoculation which did not die was that of a pig, which showed local inflammation round the site of inoculation but no glandular swelling, and is now twenty-two days after-still alive but apparently not quite well. The seventeen sub- cutaneously inoculated animals which died were 4 rabbits, 10 guinea-pigs, and 3 mice. The five inoculated by the intestinal tract and killed were 1 monkey and 4 guinea-pigs. The death of the six cases which died without inoculation is to be attributed to some of them being purposely kept in cages in which plague animals had been kept and which had not been cleaned and washed in carbolic acid solution as usual, whilst the monkeys were kept under the cages of the other animals so that food, urine and fœces were freely allowed to bespatter their cages. Death occurred in the rabbits and guinea-pigs in from 2 to 6 days after inoculation. One monkey died in five days, the pig in twenty-two days, the mice in
■from twenty-four to forty-eight hours.
Remarkable points are that in all the cases of subcutaneous inoculation the tissue round the spot of abdominal incision was infiltrated and from there to the glands of the axilla and groin lymphangitic chords could be seen, and the glands of these two cases could be seen swollen as in human plagne cases. The glands in the mesentery were swollen in nearly all cases. The cases dying after feeding with plague tissues or pure cultures showed diarrhoea in one pig and one monkey, the stomach and intestine showed sugillation, catarrlı and swelling of the mesenteric glands as well as of the external glands.
These observations justify the opinion that the plague can enter the body-
(1) By the skin.
(2) By the intestinal tract,
There were no cases in this epidemic which I saw where signs of local inflammation round wounds were evident and there are only two cases reported in Hongkong by Dr. Lowson and Dr. AOYAMA, in which plague with lymphangitis from cutaneous wounds the case of AOYAMA himself and NAKAHARA; but even here the opinions and reports differ. But as in- oculation has undeniable success the possibility certainly exists. Infection by the stomach is possible, as 50 % of the cases operated on by feeding experiments succeeded. This percentage means much more than the wounding experiments, as it approximates closely to the natural conditions of life, in fact gives a method of infection without artificial means. We may thus argue that in many cases where the plague bacillies renches the intestinal tract the disease may attack the body. This possibility is proved by the above experiments. Whether the healthy stomach is able to digest these gerins when introduced can only be answered after more animal experiments have been carried out.
Hongkong, May 20th, 1896.
DR. M. WILM.