488 
ROYAL AGRICULTURAL SOCIETY OF ENGLAND. 
disease confers a certain degree of protection from subsequent attacks 
communicated in the same way; so far, at any rate, as the experiments 
had been carried. 
2. I showed also that the fungus which constitutes the essential con- 
tagium, when grown in successive generations in a cultivating fluid, was 
still capable of giving rise to the disease, being in one case fatal to a 
cow in the first generation, in another fatal to a sheep in the fourth 
generation. My experiments also showed that an attack thus commu¬ 
nicated, causing severe symptoms, appeared to be equally protective 
against results from future inoculations with the disease given directly 
from the guinea-pig. 
I pointed out that, although I applied as severe tests as were at my 
command to ascertain the degree of protection conferred, it was yet 
desirable to perform the more crucial test of direct contagion from 
another bovine animal; and that, if the experiments were successful, 
tbe precise method of performing the protective inoculation, and the 
durability of the protection, would require further investigation. Having 
regard, also, to the small number of animals as yet experimented on, it 
would be desirable to repeat similar trials on others. 
Keeping these points in view, I have continued the experiments, and 
have inoculated two other animals with similar results. In one case 
also which had just recovered from the first attack at the time of my 
report, I have ascertained by further inoculations that protection had 
been conferred. Thus in all, I have added three more to the cases of 
success by this method. In one of these the disease was given by the 
fourth generation of the cultivated fungus, and the symptoms were 
severe. 
So far as concerns the crucial experiment, that of exposure to direct 
contagion from another bovine animal, I have not as yet had any oppor¬ 
tunity of making it, and am still waiting the occurrence of some outbreak, 
of which I hope we may receive early information. But I have just 
received some material from other animals which is known to be highly 
infectious, and am about to make experiments with it. 
Since my previous report another very interesting and equally im¬ 
portant point has become clear, which may, I hope, prove of great 
value in future. It is that, when the virus of the disease (the fungoid 
organism known as Bacillus anlhracis) is artificially cultivated in an in¬ 
different fluid, by the method of successive generations which I have 
described in my report, each succeesive generation becomes less active 
than its predecessor, and when inoculated, acts not only with less 
intensity, but more gradually, and often in a somewhat different manner. 
This modification takes place to such a degree that when the cultivation 
has been carried to the 14th or 15th generation it may be introduced 
with impunity into the system of a mouse, which is one of the animals 
most susceptible to the poison. 
Apart from its scientific interest, this fact will doubtless prove to be 
of practical value, for by its means it will be possible to obtain a virus 
of sufficient activity to produce an attack of the disease which shall be 
protective, but not of sufficient severity to be dangerous, or in any way 
injurious to the animal inoculated. 
With regard to any apprehended ill-effect upon the animals thus inocu¬ 
lated, I may say that the cows which we have used have thriven 
remarkably well, and none so well as that which has been more severely 
tested. 
I hope in a future report to give the details of these investigations, 
which have necessary been extensive and complicated. 
