I 



circumstances as well, of which we possess as little 

 knowledge as of the varying toxigenic power of the diph- 

 theria bacillus. It is this enigmatical uncertainty on all 

 the chiet points, that makes the production of serum 

 both very expensive and very precarious. The Labora- 

 tory has during the past years left no stone unturned 

 to gain light on these points. But it has met with no 

 greater success in arriving at fully satisfactory methods 

 of work than the many other European or American 

 serum laboratories which have, of recent years, placed 

 their experience at our disposal. For that reason I shall 

 refrain from entering into particulars with regard to 

 the technique used in the Deparment. The more so 

 as, in working it out, we have had to consider the very 

 unfavourable conditions under which the Department 

 had to work. I will only state that our method of im- 

 munisation follows very closely upon that applied by 

 Dr. Dean at the Jenner Institute for Preventive Medicine. 

 It is Dr. Dean, too, whom we have to thank for so 

 kindly supplying us with the race of diphtheria bacillus 

 (Park & Williams no. 8) which we are now using. The 

 methods of measuring are, of course, those of Ehrlich. 

 This eminent pathologist has, during the whole existence 

 of the Department, assisted us in every possible way, 

 and I take this opportunity to express to him my deep- 

 felt gratitude. 



Even though our Laboratory is as ignorant of the 

 conditions under which strong toxin and strong anti- 

 diphtheric serum are produced as all other labora- 

 tories, we have, no less than they, succeeded, during our 

 continuous work, in increasing the strength of the serum 

 to a much higher degree than formerly. 



In June 1895, the first antidiphlheric serum produced 

 in the Department was sent to the Blcgdam Hospital 



6 



