416 HARRIET LESLIE WILCOX 



owing to the great variation of the different stomachs. We are 

 accustomed to make about fifteen liters of pepton solution for 

 one preparation of toxin broth. This amount requires seven or 

 eight stomachs according to the size. At the Pasteur Institute, 

 marmites or large casseroles holding not less than 60 liters are 

 employed for the digestion of the pigs' stomachs. 



BERNA PEPTON 



About this time our attention was called by Dr. Noble of the 

 New York State Laboratory to a pepton put on the market by 

 the Swiss Vaccine and Serum Company, of Berne, Switzerland. 

 The statement that this pepton was made according to Witte's 

 recipe was received with some skepticism but the thought did 

 occur to us that this might be a means of getting Witte pepton 

 into the Allied countries. 



A small amount of broth (about 15 liters), was made up accord- 

 ing to our usual method using the "Berna" pepton instead of 

 the Witte. So interested were we in the result, that a small 

 amount was withdrawn from one of the flasks, filtered and tested 

 on the sixth day of growth. The minimum lethal dose was 

 found to be over 1 : 10,000 after even this short incubation period. 

 At the end of fifteen days the rest of the cultures were filtered 

 and tested. The pig which received 1 cc. of a dilution of 1 : 45,000 

 died of tetanus on the fourth day. A second preparation of 

 toxin broth made with this pepton yielded a toxin of 1 : 100,000 

 in potency. 



Broth made with Berna pepton has been used at the Bureau 

 of Laboratories since May, 1918, to the present time with favor- 

 able results for the production of tetanus toxin (see table 6). 

 The variations in the quarterly averages were greater than when 

 Witte pepton was employed. 



The average toxicities as given in this table showed again that 

 the seasonal factor was of no importance in the production of 

 potent toxins. The second quarter in the years 1918, 1919 and 

 1920 gave averages of 1:72,000, 1:21,000 and 1:16,000 respec- 

 tively. The third quarter of these same years showed still 



