Sessional_Paper_1897 — Page 446

441.

The bacillus diphtherice was first demonstrated in diphtheritic false membrane by KLEBS in 1883. In 1884 it was isolated in pure cultures and its pathogenic power was demonstrated by LOEFFLER.

Morphology.—

m.m.,

It occurs as rods straight or slightly curved with rounded ends, having a diameter of 0.5 to 0.8

and from 2 to 3 m.in. in length.

Irregular forins are very common, and indeed are characteristic of this bacillus.

In the same culture very great differences in form and dimensions may be observed.

It is stained by the use of Loeffler's solution of nethylene blue, and also by the carbolated solution of fuchsin.

The extremities of the rods are more highly refractive than the intermediate portion and in stained preparations these are seen to be most deeply coloured.

The diphtheria bacillus is aërobic, non-motile and non-liquefying, as you will see in the cultures before you; it does not form spores. It grows most freely in the presence of oxygen.

Development occurs in various culture media at a temperature of from 20° to 40° C., the most favourable temperature being about 35° C.

Milk is a favourable medium for the growth of this bacillus, and, as it grows at a comparatively low temperature (20° C. or 68 F.) it is evident that this fluid may be the medium for conveying the infection.

Pathogenesis.-

In view of the evidence recorded it may be considered as demonstrated that the bacillus gives rise to the morbid phenomena which characterise the fatal disease in man known as diphtheria.

Sheep, rabbits, cats and guinea-pigs are susceptible to this disease, pigeons are but to a modified

extent.

Roux and YERSIN showed that symptoms are produced in pigeons by the subcutaneous inoculation of 5 c.c". or more, but they commonly recover when the quantity is reduced to 2 c.c*.

KITASATO maintains that he can obtain from sheep a stronger anti-toxin.

The rat and mouse have a remarkable immunity from the effects of this poison; thus, according to Roux and YERSIN, a dose of 2 c.c., which would kill a rabbit in sixty hours (weighing three kilogrammes), is without effect on a mouse which weighs only ten grammes.

After subcutaneous inoculations of the pure culture of the bacillus in guinea-pigs, which by the way are more susceptible to this disease than any other of the lower animals, the usual changes observed at the autopsy of death are :--

An extensive local cedema, with more or less hyperemia and ecchymosis at the seat of inoculation, swollen and inflamed lymphatic glands, increased serous fluid in the peritoneum, pleura and pericar- dium, occasionally slightly swollen spleen, and sometimes fatty degenerations in the liver, kidney and myocardium; the bacillus being only found at the seat of inoculation.

BRIEGEL and FRANKEL have succeeded in rendering guinea-pigs immune against virulent cultures of the diphtheria-bacillus by injecting bouillon cultures of the diphtheria bacillus, three weeks old, which had been sterilised by exposure for an hour to 60° to 70° C. into the subcutaneous tissues, the amount used being from 10 to 20 c.c3.

According to Roux and YERSIN " attenuated varieties" of the diphtheria bacillus may be obtained by cultivating it at a temperature of 39.5° to 40° C. in a current of air.

Immunity appears to result from the introduction of a substance which is not identical with the toxic product to which the cultures owe their pathogenic power.

This latter is destroyed by a temperature of from 55° to 60° C. while the substance which gives immunity is still present in the cultures after exposure to a temperature of from 60° to 70° Č., as shown by the protective results of inoculations made with such cultures.

J. M. ATKINSON.

Appendix B.

GOVERNMENT CIVIL HOSPITAL,

HONGKONG, 29th March, 1897.

SIR, I have the honour to report that I took over charge of the Vaccine Institute in 1895 and commenced work in October of that year, (see C.S.O. No. 1,342 of 1895).

The Institute was open from October 11th, 1895, to May 31st, 1896, during which time 2,374 capillary tubes of calf lymph were produced, 414 of these were sold realising $153.80, the remainder being distributed to the Public Vaccinators, Tung Wah Hospital. Alice Memorial Hospital and the various Government Institutions.

Among those supplied with lymph during the winter of 1895 and 1896 were the following :-

Army Medical Staff.

Navy.

Dr. HILL, Pakhoi..

Messrs. DAKIN CRUIKSHANK & Co.

A. S. WATSON & Co., LD.

12