DIPHTHERIA AND SEPTIC SORE THROATS 331 



Milk. The changes in recently boiled milk, inoculated with 

 this organism and cultivated anaerobically, are characteristic. 

 Much gas is formed ; the casein is coagulated and the surface is 

 covered with pinkish scum enclosing gas bubbles. The whey 

 below is clear and colourless, has a strongly acid reaction and 

 rancid smell, butyric acid being produced. 



Ex. 151. Test samples of milk for B. enteritidis sporogenes : 

 (f) Add 10 c.c. of the milk to a sterile tube; plug and heat 

 at 80 C. for 15 minutes. Place the tube in a wide 

 Buchner tube (Fig. 25) containing pyrogallic acid and 

 caustic potash ; seal so as to secure anaerobic conditions 

 and incubate at 37 C. for two days. Pinkish frothy 

 scum appears if B. enteritidis sporogenes is present, 

 (ii) Try the same experiment, using 20 c.c. of milk, 

 (iii) Try the same experiment, using i c.c. of the milk, adding 

 it to a tube of sterile milk. 



6. Diphtheria and Septic Sore Throats. Several 

 outbreaks of true diphtheria have been traced to the 

 milk-supply, and in the majority of instances there has been 

 definite evidence to show that the bacillus of the disease 

 found its way into the milk from human sources and did 

 not come from the cow. At the farm or dairy supplying 

 the milk one or more persons were suffering from diph- 

 theria or had only recently recovered from it. In many 

 cases of mild throat epidemics similar evidence of the 

 human infection of the milk is generally forthcoming. 



There are, however, many instances where epidemic 

 " septic " sore throats of a more or less diphtheritic 

 character have been set up by milk given by cows 

 suffering from various obscure forms of mastitis or 

 inflammatory diseases of the udder 



