xvii INTRODUCTION 
At this time knowledge of physiological chemistry was but little advanced. 
It is only now, fifty years after Lister’s work, that we are beginning to arrive 
at an adequate interpretation of the complicated phenomena of coagulation, 
and that an answer to the question with which Lister was confronted is 
forthcoming. At that date all that could be vouchsafed to the most patient 
and gifted experimenter was to remove false conceptions and accumulate 
a number of accurate observations to serve as guide-posts for future workers. 
This Lister accomplished. He showed the untenability of the then prevalent 
theory of Richardson that coagulation was due to the escape of ammonia when 
blood was shed. Both in so doing and afterwards in seeking for an explanation 
why blood should comport itself so differently when in healthy living vessels, 
and when in contact with ordinary solids, he discovered a large number of 
cardinal facts concerning coagulation which have been, and will in the future 
still be, of service to investigators in their efforts towards complete under- 
standing of the phenomena of the clotting of blood. 
SURGICAL WORK 
A just conception of the value of Lister’s surgical work can only be formed 
if the state of surgery and the conditions of surgical practice towards the middle 
of the last century are borne in mind. The results of surgical operations are 
now so generally good that it is hard to realize what they were before Lister 
began his reform. At that time, though they naturally varied a good deal 
in different hands and under different sanitary conditions, the broad facts 
with regard to the very unsatisfactory results of the surgical treatment 
of wounds and the dangers of operations were much the same in every 
country and in every hospital. Putrefaction of the discharges present in and 
escaping from the wounds occurred in almost every case, and was accompanied 
by more or less local inflammation. Wounds were, during their early stages, 
swollen and painful, and this local inflammation was constantly attended by 
more or less fever, which usually lasted for several days. Union by first in- 
tention was of very rare occurrence ; it was indeed impossible in large wounds, 
owing to the fact that the ligatures with which the vessels were tied had 
subsequently to be extruded by a process of granulation and suppuration ; the 
suppuration which necessarily occurred along the track of the ligatures usually 
spread to the rest of the wound. Associated with this process of separation of 
the ligatures was another danger, from the dread of which the surgeon’s mind 
was never free: this was the fear that the process by which this separation was 
brought about might open up the lumen of the vessel, and lead to so-called 
secondary haemorrhage. 
