94 ESSAYS ON BACTEEIOLOGY. 



Alongside of these cases, and in tlie same hospitals, 

 ■with the same fayorable surroundings, 5,706 cases of 

 diphtheria were treated by the old method, with a 

 death-rate of 42.3 per cent. 



"There was, therefore," says Dr. Welch, "an appar- 

 ent reduction of case mortality by the use of antitoxin 

 of 55.8 per cent." 



Statistics, according to the age of the patient, both 

 with and without the serum treatment, afford very in- 

 teresting reading. 



Erom a summary of this table, Welch says: "Of 

 1,729 cases of diphtheria with a fatality of 14.9 per 

 cent., 1,115 cases treated with antitoxin during the 

 first three days of the disease yielded a fatality of 8.5 

 per cent., whereas 546 cases in which antitoxin was 

 first injected after the third day of the disease yielded 

 a fatality of 27.8 per cent. 



"Of 232 in which treatment was begun on the first 

 day five died, or 2.16 per cent. Of 492 cases in 

 which treatment was begun on the second, day 30 

 died, 7.7 per cent. Of 331 cases in which treatment 

 was begun on the third day 43 died, 13 per cent. ; on 

 the fourth day 19 per cent., on the fifth day 29.3 per 

 cent., on the sixth day 34.1 per cent." 



In closing his report Dr. Welch makes this state- 

 ment: "The principal conclusion which I would 

 draw from this paper is that our study of the results 

 of the treatment of over 7,000 cases of diphtheria by 

 the antitoxin demonstrates beyond all doub); that anti- 



