170 Diseases of Poultry 



a number of experiments in this line have been conducted both 

 in this country and Europe. Some workers have tried as a 

 curative agent the antitoxin prepared for human diphtheria. 

 Others have used serum prepared from small mammals and 

 fowls which have recovered from the disease. Still others 

 have attempted to establish an immunity in healthy fowls 

 and also to cure diseased birds with vaccines prepared from 

 cultures of the organisms isolated from the lesions. Dif- 

 ferent investigators disagree as to the effectiveness of each of 

 these methods of treatment. The disagreement of their 

 results may be due to the variation in virulence of the cul- 

 tures with which they worked. 



Hopeful results have been lately obtained in this country 

 at Ohio State University and at Purdue. The following 

 brief account of the preparation of the vaccine and the method 

 of treatment used successfully at Purdue and on nearby farms 

 is given by Philips.^ 



"Cures and methods of cure for roup are so varied and 

 uniformly unsatisfactory that it was thought advisable to 

 experiment with roup vaccine. This vaccine was first made 

 at Ohio State University and proved reasonably satisfactory 

 to them. 



"The method of making vaccine is very simple. The 

 first process is to take cultures from under the ulcers and 

 grow them from 24 to 36 hours on neutral agar at a tempera- 

 ture of 37.5 degrees C. Then wash off the organisms in a 

 sterile normal salt solution and attenuate them for an hour 

 and a half in a water bath at 64 degrees C. If the vaccine is 

 to be left standing it is advisable to make it one-half per cent 

 acid with carbolic acid, as this acts as a preservative. 



"The method of standardization is the most difficult part 



1 Philips, A. G., "A Preliminary Investigation with Roup." Jour, 

 of the Amer. Assoc, of Inst, and Invest, in Poultry Husbandry, Vol. 1, 

 No. 4, pp. 28-31, 1915. 



