Fepruary 18, 1897 | 
WATORE 
72) 
took up his quarters, and hastily improvising a laboratory, 
commenced his investigations. 
So far the plague had confined itself to the insanitary Chinese 
quarters of the city; and Yersin mentions that the wretched 
cabins occupied by the natives were often not only without 
windows of any kind, but were sunk below the level of the 
ground, which, combined with the shocking overcrowding 
which prevailed, converted such dens into plague-incubators of 
the most fulsome and dangerous character. 
In these infected districts, one of the first things which 
attracted Versin’s attention was the extraordinary number of 
dead rats which lay about in all directions in the houses as well 
as in the streets; but, on inquiry, he soon learnt that this rat- 
mortality was a well-known forerunner of the plague, that the 
latter usually attacks animals such as rats and mice, and in the 
country districts swine and buffalos, before it touches human 
beings. An examination of these dead rats showed that their 
symptoms differed in no way from those which characterise the 
plague in man, and the extreme susceptibility of these animals 
furnished Yersin at once with a valuable means of tracking out 
the virus. His first step was to make careful examinations of 
the bubonic material present in the tumours which accompany 
the disease, and here he discovered immense numbers of a short 
bacillus which appeared to be almost exclusively in possession 
of the field. These he found were readily stained, and could 
be cultivated with ease in the usual bacterial media. Further 
investigation showed that these same bacilli were invariably 
present in the ganglia and liver and spleen of plague patients ; 
that they were, however, rarely to be found in the blood, and 
then but in small numbers, and usually only in rapidly fatal 
cases a short time before death. 
Healthy rats and mice inoculated with pure cultures of this 
bacillus succumbed to the typical plague symptoms ; and Yersin 
had thus accomplished the first step in his investigation—the 
identification of the specific virus of plague. Yersin was at 
first of opinion that rats were the principal disseminators of the 
disease, for healthy mice shut up with a dead plague-stricken 
rat, rapidly developed the disease and succumbed; but he 
noticed later the curious fact that, in the little room where he 
carried out his fost-mortem examinations, immense numbers of 
dead flies were scattered about in all directions. He, there- 
fore, determined to ascertain if this wholesale slaughter of flies 
had any connection with plague infection; so taking some of 
these insects, and first removing the head, wings and feet, he 
pounded up their bodies in broth. An examination later of the 
liquid exhibited masses of bacilli closely resembling the now 
familiar plague microbe; to place their identity beyond doubt 
he inoculated some of this broth into mice, with the result that 
the latter died of plague. That flies materially assisted in the 
spread of the disease was thus established. 
With the slender accommodation and primitive means at his 
disposal, it was impossible for Yersin to further pursue his in- 
vestigations, and prepare a plague anti-toxin, and he, therefore, 
forwarded cultures of his bacillus to the Institut Pasteur, and 
from here, in the course of the following year, was published 
the memoir describing the production of the anti-plague serum 
which is now being so urgently requisitioned for service in 
India. The bacillus was found to be pathogenic for not only 
rats and mice, but for the other animals of an experimental 
laboratory, rabbits and guinea-pigs. 
The attempt was first made to vaccinate these animals by means 
of the toxin, but filtered cultures of the bacillus produced no 
effect whatever ; so that the plan was adopted of heating cul- 
tures to 58° Centigrade, and inoculating the dead bacilli. If the 
latter are injected in sufficient quantities, they are capable of 
killing the animal ; but if a smaller quantity of the liquid con- 
taining them is employed, then it acts as a vaccine, and the 
animal is protected from a subsequent lethal inoculation of the 
virus, and its serum subsequently acquires protective properties. 
From success with small animals the attempt was made to im- 
munise large animals, such as horses. For this purpose virulent 
plague-cultures, capable of killing a mouse in two days, were 
employed, and the liquid containing these living microbes was 
injected into the horse’s veins. The reaction was rapid and 
intense, and lasted a whole week, after which the fever abated, 
and the animal slowly recovered. A long interval—twenty 
days—was allowed to elapse before a second injection was at- 
tempted ; but this time, although an equally virulent culture was 
employed, in the same quantity as before, the symptoms were 
less pronounced, and passed away more rapidly, and it was 
NO. 1425, VOL. 55 | 
found possible to both gradually increase the quantity and 
diminish the interval between the several injections. At the 
end of six weeks the first trial was made of the curative pro- 
perties already attained by the serum, and the results were 
regarded as extremely satisfactory and encouraging. To confer 
immunity to plague infection on a mouse, it required 5th of a 
cubic centimetre of serum, administered twelve hours éefore the 
virus was injected ; to cure animals after plague infection, 15 cubic 
centimetres of serum were required to be inoculated twelve hours 
after the virus had been introduced. The large quantity of 
serum necessary in these first experiments for curative purposes, 
was due to the short time during which the immunising process 
had been carried on. It will be remembered that in diphtheria 
the time required to train a horse’s serum up to the proper pro- 
tective pitch is a question of months, and in the case of anti- 
venomous serum a matter of as much as fifteen months; thus a 
treatment of six weeks only is a very short time for the serum to 
exhibit immunising properties. That the most remarkable thera- 
peutic value attaches to anti-plague serum as now elaborated at 
the Institut Pasteur in Paris, is shown by the success which has 
recently followed its application in undoubted cases of plague at 
Amoy, by Yersin, now Director of a Pasteur Institute at Nha- 
Trang in Annam. 
In conclusion, it may be asked, How long is England to rest 
content to knock as a humble suppliant at the door of foreign 
institutes for assistance when overtaken by disaster, as is now 
the case in India? Why should Paris supply the means for 
relieving the suffering of our fellow-subjects in India? 
The answer and reasons for that answer are, alas! but too 
well known to require repetition here ; and we can only hope 
that in the future, at present dim and obscure, the barriers which 
now so formidably impede medical progress in this country may 
yield before the enlightened pressure of public opinion. 
G. C. FRANKLAND. 
THE “BAZIN” ROLLER BOAT. 
N Nature of December 3, 1896, we gave a short notice of the 
new roller-boat the Zynest Bazin. From a paper recently read 
at the Society of Arts by M. Emile Gautier (ournal Society of 
Arts, January 22), the following further particulars are taken. 
The Ernest Bazin was launched a few months ago at Saint- 
Denis, and was then taken down the Seine to Rouen, where she 
is being fitted with her engines and machinery. As soon as 
these are completed an experimental trip will be made across 
the Channel, and it is anticipated that the vessel will in the 
course of about six weeks be anchored in the Thames. This 
experimental vessel has a displacement of 280 tons ; its length is 
131 ft. 3 in., and width 38 ft. 9 in. The framework and hull 
are supported on six lenticular hollow wheels 32 ft. 10 in. in 
diameter, about one-third of which will be immersed. The 
engines, cargo, cabins, Xc., are placed on a platform resting on 
a framework carried on the axles of the wheels. The engines 
are constructed to develop 750 horse-power ; 550 of which will 
be used for the propeller, and 200 horse-power for driving the 
three pairs of wheels. With this power an ordinary steamer of 
a similar tonnage would not steam more than 18 or 19 knots. 
It is expected that the Arvest Bazin will attain double this 
speed. The principle on which the vessel is constructed is the 
substitution of the rolling motion of great wheels for the 
ordinary gliding motion of the hull of the vessel through 
the water, in order to minimise friction. An ordinary ship 
with its hull gliding through the water represents the disc 
pushed forward without a rotary motion being imparted to it. 
‘As it is compelled to cut the water in front of it, and to drive it 
back longitudinally, it would soon cease to move forward did it not 
receive a fresh impulsion at every moment. If, however, the vessel 
were supported by revolving buoys, it is contended that it would 
possess all the advantages of the disc, to which a rotary as wellas. 
a forward motion is given. The effort, instead of being exercised 
longitudinally, is exercised partially downwards, vertically, so. 
that the resistance is reduced in a considerable degree. 
‘As the result of calculation the rotary speed of the wheels has 
been made one half greater than the speed of translation. 
In the discussion which followed the reading of the paper, the 
speakers, while declining to prophesy as to the results to be 
attained, seemed to be of opinion that the difficulty of con- 
struction would increase very rapidly with the increase in size, 
owing to the great strain which would be imposed on the 
