16 
FR. BLAZEKOVIC. 
virus first receives its activity as an infectious element when it 
has suffered certain metamorphoses in the diseased part, or has 
favored the development of certain zymotic elements or fungi in 
the same, while contagium acts directly, independent of the grade 
of development, or the progression of the disturbance from which 
it proceeds, and it is not necessary that a certain period of 'de¬ 
velopment of the same be attained before it becomes active. Its 
action is not limited by any period of development, let the infee- 
tion’s-centre come from whence it will. 
This disease is without doubt infectious, yet, according to my 
observation and experience, it contains no specific contagium ; 
but the disease must pass through certain phases before its secrete 
attains its infectious properties; hence , the disease is not infectious 
in cdl stages of its course. The infectious nature of the disease is 
accordingly virulent, but, as the infectious elements are not of a 
transportable character, the pest-like extension of the disease is 
much more insignificant than by pests characterized by easily 
transportable infectious elements. 
A limitation to the extension of this disease by means of its 
infectious elements results from the circumstance that the activity 
of these elements is limited to a period conformable to the pathic 
. processes. This, with the previously considered causes, may well 
be causa sujficiens that the disease does not assume an epizootic, 
but always retains an enzootic character, even though at times 
presenting itself as a virtual pest. 
In many medical works on ophthalmology we find various 
remarks over the extension which such diseases at times acquire 
by means of infection, yet we do not find any author ascribing to 
the infectious elements a highly portable character. The exten¬ 
sion finds its best explanation in uncleanliness, especially among 
the working classes ; while ophthalmologues frequently give evi¬ 
dence of one eye becoming infected by transmission of the infec¬ 
tious elements at the hands of the person diseased. I have been 
unable to constitute any such case, by the disease in question, 
among horses. In all cases, only one eye was primarily diseased, 
and, as said, an infection of the other by infectious elements from 
the diseased has not come to my observation. If both eyes were 
