“I proceeded very cautiously. After I had treated some adult diphtheria patients with ordinary horse serum in 1911, I began in 1912 to treat alternate adult patients with antitoxin serum and with ordinary serum, exactly in the temporal sequence in which they were admitted to the ward. The children all received antitoxin serum. In the second half of the year 1912 and in the first half of 1913, I gradually lowered the age of those to be treated with ordinary horse serum, and from 1 July 1913 every second case was treated with ordinary horse serum, whether child or adult, regardless of the severity of the illness or the presence of complications. I note that it is absolutely inadmissible to compare the results for different time periods, for example to give antitoxin serum during one year, and then to give only ordinary horse serum during a second year, and then to compare the results. That would lead to seriously wrong conclusions, for in no infectious disease is the nature of the epidemic so changeable as in diphtheria. Mostly we see light epidemics, but quite serious ones still occur. I remind [the reader] of the heavy epidemics in Berlin and Hamburg of the year 1910, and the one in Leipzig of 1914, which recall the bad times of the period before serum. The table on p286-7 shows how many patients were treated in each year and the number of deaths.”
[p288, last para, on blinding of assessors]
“To make the trial as objective as possible, I have not relied on my own judgment alone, but have sought the views of the assistant physicians of the diphtheria ward, without informing them about the nature of the serum under test (namely the ordinary horse serum). Their judgement was thus completely without prejudice. I am keen to see my observations checked independently, and most warmly recommend this “blind” method for the purpose. Even the chief physician may try to draw conclusions about the nature of the serum (unknown to him) that has been used in a particular case: he will be astonished to see how little he is able to do this…….Neither I nor my assistants Dr Reusz, Dr Schwab, Dr Weber, Dr Lube could detect a difference between the two sera. Dr Koennecke thought the old (antitoxin) serum had a certain advantage, while Dr Rehder declared that if he were to fall ill, he would wish to be treated with the new (horse) serum. The views of these two gentlemen thus neutralised each other.”
The editors are grateful to:
Andrew Herxheimer for translating the key passages.