White Diarrhea 297 



however, with both acid and gas production. In the dextrose 

 fermentation tubes about 20 per cent of the closed arm 

 is filled with gas, and the mannite tubes average about the 

 same. The gas consists of CO2 and H in the ratio of 1 : 3. 

 Some of the strains do not produce gas in any of the sugar 

 media, though acid production is quite apparent. 



Indol and Nitrate Production. — Neither indol nor nitrate 

 could be detected in Dunham's peptone solution at the end 

 of one week's growth in the incubator. 



Quite recently still another method for the diagnosis of 

 this disease has been proposed. Jones ^ points out that the 

 bacteriological examination of eggs is an unsatisfactory 

 method of detecting fowls that are harboring this germ in the 

 ovary. This arises from the fact that with such an infected 

 hen only occasional eggs may contain this organism. Yet 

 such a hen is a source of danger to the flock. Jones then 

 suggested the use of the agglutination test. This test con- 

 sists in adding a very small quantity of the blood serum of a 

 suspected fowl to a dilute (milky) suspension of the bacteria. 

 If the fowl has the disease the bacteria will clump together 

 and settle to the bottom of the test tube so that the liquid 

 above will appear clear. If the bird is not affected the 

 bacteria will not clump together and the suspension will 

 retain its milky appearance. 



This test has now been used by Jones, Gage ^ and Rettger, 

 Kirkpatrick and Jones.^ In all of these studies it has proved 

 to be an important aid in the recognition of this infection in 

 laying hens. 



1 Jones, F. S., "The Value of the Macroscopic Agglutination 

 Test in Detecting Fowls that are Harboring Bacterium pullorum.'^ 

 Jour. Med. Res., Vol. 27, pp. 481-495, 1913. 



2 Gage, G. E., "On the Diagnosis of Infection with Bacterium 

 pullortan in the Domestic Fowl." Mass. Agr. Expt. Stat. Bui. 148, 

 pp. 1-20, 1914. 



' Loc. cit. 1914. 



