DIPHTHERIA. 417 



As the quantity to be injected at each dose diminishes 

 according to the number of units per cubic centimeter 

 the serum contains, it is of the highest importance that 

 the serums be as strong as possible. Various methods of 

 concentration have been suggested, such as the partial 

 evaporation of the serum in vacuo, but none have proved 

 satisfactory. Bujwid 1 and H. C. Ernst 2 find that when an 

 antitoxic serum is frozen and then thawed, it separates 

 into two layers, an upper watery stratum and a lower 

 yellowish one ; the antitoxic value of the yellowish layer 

 is about three times that of the original serum, the sepa- 

 rated upper layer being chiefly water. 



Ehrlich asserts that 500 units are valueless for treat- 

 ment: 2000 units are probably an average dose, but, as 

 the remedy seems harmless, it is better to err on the side 

 of too much than on that of too little. Forty thousand 

 units have been administered with beneficial results. 



It is a common clinical experience that paralysis is 

 more frequent after the use of antitoxin than in cases 

 treated without it. In a paper upon this subject 3 I have 

 shown that this is to be expected, as the palsies usually 

 occur after the bad cases of the disease, of which a far 

 greater number recover when antitoxin is used for treat- 

 ment. 



The largest collection of statistics upon the results of 

 antitoxic treatment in diphtheria in the hospitals of the 

 world are probably those collected by Prof. Welch, 4 who, 

 excluding every possible error in the calculations, "shows 

 an apparent reduction of case-mortality of 55.8 per cent." 



One of the most important things in the treatment is' 

 to begin it early enough. Welch's statistics show that 

 1 1 15 cases of diphtheria treated in the first three days 

 of the disease yielded a fatality of 8.5 per cent., whereas 



1 Centralbl. f. Bakt. u. Parasitenk., Sept., 1897, Bd. xxii., Nos. 10 and 11, 

 p. 287. 



* Journal of the Boston Society of the Medical Sciences, May, 1898, vol. ii., 

 No. 8, p. 137. 



3 Medical Record, New York. 1897. 



* Bulletin of the Johns Hopkins Hospital. 



27 



