POISONS AND THEIR PREVENTION 169 



are engaged upon opening up new tracts, in 

 overcoming difficulties, in changing chaos into 

 order. 



The problems which surround immunity are of 

 so complex and subtle a character that their mas- 

 tery is by no means either easy or rapid, and 

 many recondite researches appear at frequent 

 intervals on this subject in foreign and other 

 scientific journals, rendering it a difficult matter 

 to keep pace with the new discoveries and the 

 latest theories. 



The interest in this country in toxins and anti- 

 toxins not unnaturally centres round that branch 

 of the subject which deals with diphtheria, this 

 disease having of late years figured so prominently 

 in our mortality tables, whilst the production of 

 diphtheria and other anti-toxic serums has been 

 so finely elaborated abroad that it already consti- 

 tutes an article of commerce, and doubtless helps 

 to swell the exports of our great continental com- 

 mercial rival. 



In this connection the following statistics, pub- 

 lished by Dr. Jalzer, of the Miilhaus Hospital, 

 are of interest regarding the mortality from 

 diphtheria before and after the introduction and 

 application of diphtheria anti-toxin. The death- 

 rate from this disease, writes Dr. Jalzer, which in 

 1892 and 1893 was fully 50 per cent., fell in 1895 



