102 
Proceedings of the Royal Irish Academy, 
cornea itself. The corneas were excised and examined at intervals 
varying from a few hours to eight or ten days after the infliction of 
the injury ; sometimes in the fresh condition in the moist chamber and 
immersed in aqueous humour or some other indifferent fluid, sometimes 
after staining by chloride of gold or carmine. 
In all cases the changes observed were essentially the same in kind, 
but infinitely variable in degree. A condition which in one animal was 
produced in a few hours, would in another require two or three times 
as long for its production, and this without my being able to explain 
the delay by any unusual condition of the animal under experiment. 
Furthermore, in very few instances was the inflammatory process equally 
advanced in all parts of the same cornea, but parts at the same distance 
from the point of irritation were found at all stages of the inflammation 
in widely different states ; and in many cases, in different parts of the 
same specimen, all appearances could be seen, from a tissue swarming 
with pus corpuscles, and presenting no other formed elements, to one in 
which the normal condition of the cornea was scarcely departed from. 
I shall therefore say very little of the time required for the production 
of each stage in the formation of pus. In all instances this time was 
in my hands greater than that found necessary by German experi- 
menters, a fact which I attribute to the greater feebleness of our frogs 
to which I have already alluded. 
I may state at the outset that I have found in no single instance 
the state of things described by Cohnheim. In no case have I seen the 
connective tissue corpuscles of the cornea lying unaltered amidst the 
pus cells. In every case, pari passu with the appearance of pus, the con- 
nective tissue cells disappeared , and hence, while in no way denying 
the immigration of white corpuscles from without, I am fully convinced 
that the great mass of the pus corpuscles are formed in the cornea itself 
from the connective tissue cells. It will be the object of the remainder 
of this report to describe the forms intermediate between these two 
kinds of cells. 
Passing over a slight, and not always very evident, swelling of the 
connective tissue cells, the first very marked change which we observe 
in these is a tendency to become elongated in one direction. They 
thus lose their equally stellate shape, and while the processes or rays 
at the two sides are drawn in, those at the ends may persist for some 
time. The nucleus accommodates itself to the shape of the cell, and 
assumes also an elongated form. The protoplasm is at this period more 
granular than in the healthy cell. The tendency of the cornea corpuscles 
to become more or less spindle-shaped when irritated, and after the 
removal of the irritation, to resume their natural form, has been known 
since the publication of the beautiful researches of Kiihne^ on the 
protoplasmic movements of animal cells. When the irritation is very 
* Untersuchungen iiber das Protoplasma und die Contractilitat. Von Dr. W. 
Kuhne. Leipzig, 1864, s. 121 et seq. 
