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EXPERIMENTAL PATHOLOGY. 
The prevention of small-pox by vaccination has been a grand 
and wonderful success—it is the one solitary success to which the 
medical profession can point with pride in its long struggle with 
the indigenous, contagious diseases. And this we are told is not 
worth imitation, because it is the blind method of nature. What 
is there so terrible in gaining immunity through actual disease as 
is practiced on so large a scale in this same vaccination? And 
who dare predict at this time that we shall not, in a few years, 
have the virus of the greater part of the contagious diseases so 
mitigated that their effects will be as mild as those of vaccine 
lymph ? 
There is another possibility even more desirable than this. 
We have seen that immunity is acquired by the cells becoming 
accustomed to the action of a certain poison excreted by the dis¬ 
ease germ. Suppose, as the result of such studies, the chemist of 
the future is able to separate this substance from the germs and 
supply it, as quinine is now supplied, in a condition of purity. 
And suppose, as is very likely, that the introduction of this sub¬ 
stance into the tissues would confer as complete an immunity as 
occurs when it is produced there by the germs, would this not be 
a solution of the question worthy of many years’ investigation ? 
Until we succeed better than we have in the past in destroy¬ 
ing the germ before it attncks the man, let us not insist upon this 
method to the exclusion of all others, at least so long as over two 
hundred thousand of our population annually testify by the sac¬ 
rifice of their lives to the insufficiency" of this method. 
EXPERIMENT L PATHOLOGY. 
(Extracts from the Eevue des Sciences Medicales.) 
EXPERIMENTAL RESEARCHES ON CICATRIZATION IN BLOOD 
VESSELS AFTER LIGATURE. 
By N. Senn. 
After considering the entire history of ligation from the 
climco and anatomo-pathological point of view, the author reports 
numerous experiments undertaken to confirm the facts already 
obtained to determine the mode of cicatrization of ligated blood 
vessels. His conclusions are as follows : 
