ON THE EARLY STAGES OF INFLAMMATION 20T 
closely packed as to present the appearance of a uniform crimson mass; and 
by and by the epidermis will be found raised in the form of a blister over the 
part on which the mustard lay. These effects are precisely similar to those 
which we have seen to be produced by it upon the human skin; and before 
effusion has taken place, the vessels of the affected part exactly resemble those 
of the congested spot of inflamed pia mater above described. Again, if dry 
heat be made to act upon a part of the frog’s foot, there will result, in proportion 
to the elevation of the temperature and the duration of its action, undue redness 
of the vessels from accumulation of the blood-corpuscles ; and if the burn have 
been sufficiently severe, vesication will soon take place as in the human subject. 
These and other similar cases indicate that the early stages of inflammation 
are alike in man and in the frog, and this conclusion is fully confirmed by 
examination of the bat’s wing, which furnishes the means of watching the effects 
of irritants upon mammalian circulation. The very small size of the blood- 
corpuscles, and some other circumstances, render that animal much less suitable 
for the investigation than the frog; but with the use of high powers of the 
microscope and a little pains, the same sort of experiments can be made with 
both: and the careful observations of Messrs. Paget and Wharton Jones, and, 
I may add, also my own more limited experience with the bat, have shown that 
in all the details that can be observed, a complete similarity obtains between 
the effects of irritation upon the circulation in the two creatures. We may 
therefore rest fully satisfied that conclusions arrived at from the study of the 
early stages of inflammation in the foot of the frog will apply in all strictness 
to the same morbid process in man. 
It is well known that the field of observation thus afforded has not been 
allowed to remain uncultivated. Since the microscope has been brought to its 
present state of perfection, not to speak of a previous period, men of established 
scientific reputation have devoted much patient labour to it; and any one 
who now enters upon this inquiry has the great advantage of possessing faithful 
records of accurate observations made by many able predecessors. But the 
number and discordance of the views entertained by different authorities regard- 
ing the cause of the ‘ stasis’ of the blood in inflammation, are sufficient evidence 
either that the subject demands further investigation, or else that it les beyond 
the reach of human means of research. 
Having been called upon in the capacity of a teacher of surgery to attempt 
an explanation of the matter to others, I felt bound to do my best, by personal 
observation, to form a judgement for myself; and several new facts which 
I have unexpectedly met with appear to throw such fresh and clear light upon 
the nature of disease, that I venture to submit them to the Royal Society. 
P 2 
