
Fune 15, 1871 | 
NATURE 
125 

to the guidance of the germ theory he could not have 
acted more in accordance with the requirements of that 
theory than hehas actually done. It is what the air con- 
tains that does the mischief in vaccination. Mr. Ellis’s 
results fallin with the general theory of putrefaction pro- 
pounded by Schwann, and developed inthis country with 
such striking success by Prof. Lister. They point, if true, 
to acause distinct from bad lymph for the failures and 
occasional mischief incidental to vaccination ; and if fol- 
lowed up they may be the means of leaving the irrational 
opposition to vaccination no ground to stand upon, by 
removing even the isolated cases of injury on which the 
opponents of the practice rely. 
We are now assuredly in the midst of practical matters. 
With your permission I will recur once more to a question 
which has recently occupied a good deal of public atten- 
tion. You know that as regards the lowest forms of life, 
the world is divided, and has for a long time been divided, 
into two parties, the one affirming that you have only to 
submit absolutely dead matter to certain physical condi- 
tions to evolve from it living things; the others, without 
wishing to set bounds to the power of matter, affirming 
that in our day no life has ever been found to arise in- 
dependently of pre-existing life. Many of you are aware 
that I belong to the party which claims life as a derivative 
of life. The question has two factors: the evidence, and 
the mind that judges of the evidence ; and you wili not 
forget that it may be purely a mental set or bias on my 
part that causes me throughout this discussion from 
beginning to end, to see on the one side dubious facts and 
defective logic, and on the other side firm reasoning and 
a knowledge of what rigid experimental inquiry demands. 
But judged of practically, what, again, has the question of 
Spontaneous Generation to do with us? Let us see. 
There are numerous diseases of men and animals that 
are demonstrably the products of parasitic life, and such 
disease may take the most terrible epidemic forms, as 
in the case of the silkworms of France in our day. Now 
it is in the highest degree important to know whether the 
parasites in question are spontaneously developed, or are 
wafted from without to those afflicted with the disease. 
The means of prevention, if not of cure, would be widely 
different in the two cases. 
But this is by nomeans all. Besides these universally 
admitted cases, there is the broad theory now broached 
and daily growing in strength and clearness—daily, in- 
deed, gaining more and more of assent from the most 
successful workers and profound thinkers of the medical 
profession itself—the theory, namely, that contagious 
disease generally is of this parasiticcharacter. IfI had 
heard or read anything since to cause me to regret having 
introduced this theory to your notice more than a year 
ago, I should here frankly express that regret. I would 
renounce in your presence whatever leaning towards the 
germ theory my words might then have betrayed. Let 
me state in two sentences the grounds on which the 
_ supporters of the theory rely. From their respective viruses 
you may plant typhoid fever, scarlatina, or small-pox. 
What is the crop that arises from this husbandry? As 
surely as a thistle rises from a thistle seed, as surely 
as the fig comes from the fig, the grape from the 
grape, the thorn from the thorn, so surely does the 
typhoid virus increase and multiply into typhoid fever, 
the scarlatina virus into scarlatina, the small-pox virus 
into small-pox. What is the conclusion that suggests 
itself here? Itis this :—That the thing which we vaguely 
call a virus is to all intents and purposes a seed: that in 
the whole range of chemical science you cannot point to | 
an action which illustrates this perfect parallelism with the 
phenomena of life—this demonstrated power of self- 
multiplication and reproduction. There is, therefore, no 
hypothesis to account for the phenomena but that which 
_ refers them to parasitic life. 
And here you see the bearing of the doctrine of Spon- 



taneous Generation upon the question. For if the doctrine 
continues to be discredited as it has hitherto been, it will fol- 
low that the epidemics which spread havoc amougst usfrom 
time to time are not spontaneously generated, but that they 
arise from an ancestral stock whose habitat is the human 
body itself. It is not on bad air or foul drains that the 
attention of the physician will primarily be fixed, but 
upon disease germs which no bad air or foul drains can 
create, but which may be pushed by foul air into virulent 
energy of reproduction. You may think I am treading 
on dangerous ground, that I am putting forth views that 
may interfere with salutary practice. No such thing. If 
you wish to learn the impotence of medical science 
and practice in dealing with contagious diseases, you 
have only to refer to a recent Harveian oration by Dr. 
Gull. Such diseases defy the physician. They must 
burn themselves out. And, indeed, this, though I 
do not specially insist upon it, would favour the idea of 
their vital origin. For if the seeds of contagious disease 
be themselves living things, it will be difficult to destroy 
either them or their progeny without involving their living 
habitat in the same destruction. 
And I would also ask you to be cautious in accepting 
the statement which has been so often made, and which 
is sure to be repeated, that I am quitting my own sétier 
when I speak of these things. I am not dealing with pro- 
fessional questions. I am writing no prescription, nor 
should I venture to draw any conclusion from the condi- 
tion of your pulse and tongue. Iam dealing with a ques- 
tion on which minds accustomed to weigh the value of 
experimental evidence are alone competent to decide, 
and regarding which, in its present condition, minds so 
trained are as capable of forming an opinion as on the 
phenomena of magnetism and radiant heat. I cannot 
better conclude this portion of my story than by reading 
to you an extract from a letter addressed to me some time 
ago by Dr. William Budd, of Clifton, to whose insight 
and energy the town of Bristol owes so much in the way 
of sanitary improvement. 
“ As to the germ theory itself,” writes Dr. Budd, “that 
is a matter on which I have long since made up my mind. 
From the day when I first began to think of these sub- 
jects, I have never had a doubt that the specific cause of 
contagious fevers must be living organisms. 
“Tt is impossible, in fact, to make any statement bearing 
upon the essence or distinctive characters of these -fevers, 
without using terms which are of all others te most dis- 
tinctive of life. Take up the writings of the most violent 
opponent of the germ theory, and, ten to one, you will 
find them fuil of such terms as ‘ propagation,’ ‘ self-propa- 
gation, ‘reproduction,’ ‘self-multiplication, and so on. 
Try as he may—if he has anything to say of those diseases 
which is characteristic of them—he cannot evade the use 
of these terms, or the exact equivalents to them. While 
perfectly applicable to living things, these terms express 
qualities which are not only inapplicable to common 
chemical agents, but as far as I can see actually incon- 
ceivable of them.” 
Once, then, established within the body, this evil form 
of life, if you will allow me to call it so, must run its course. 
Medicine as yet is powerless to arrest its progress, and 
the great point to be aimed at is to prevent its access to 
the body. It was with this thought in my mind that I 
ventured to recommend, more than a year ago, the use of 
cotton-wool respirators in infectious places. I would 
here repeat my belief in their efficacy if properly con- 
structed. But I do not wish to prejudice the use of these 
respirators in the minds of its opponents by connecting 
them indissolubly with the germ theory. There are too 
many trades in England where life is shortened and ren- 
dered miserable by the introduction of matters into the 
lungs which might be kept out of them. Dr. Greenhow 
has shown the stony grit deposited in the lungs of stone- 
cutters. The black lung of colliers is another casein point 
