Bacillary white diarrhœa of chicks (B.W.D.) / by T. Dalling, J.H. Mason and W.S. Gordon.

  • Dalling, Thomas.
Date:
[1927?]
Catalogue details

Licence: In copyright

Credit: Bacillary white diarrhœa of chicks (B.W.D.) / by T. Dalling, J.H. Mason and W.S. Gordon. Source: Wellcome Collection.

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    four per cent, of the eggs laid over a period yielded cultures of B. pullorum. We found that contaminating organisms grow from about four per cent, of the eggs tested. We have also shown that B. pullorum, injected into eggs laid by clean hens, can be recovered after incubation for a week. 0*1 c.c. of varying dilutions of culture (1-1,000 to 1-1,000,000) was injected, and cultures were recovered from all eggs except those injected with a dilution of 1 in 1,000,000. Three eggs were used for each dilution. We (8) have already recorded that of 273 unhatched eggs, of which 127 were unfertile and 146 contained dead chicks, cultures of B. pullorum were grown from 55. These eggs were produced by hens of which 11 per cent, reacted positively to the agglutination test. Passage of B. Pullorum Through Egg Shells.—We have carried out experiments to test whether, in the isolation of B. pullorum from eggs laid by carrier hens, the organisms may have penetrated through the shell from some external sources. Two litres of broth culture of B. pullorum was prepared. Eighteen eggs from non-reacting hens, the surface of which were cleansed and dried, were soaked in the culture for periods varying from five to 60 minutes. They were then incubated for seven days and, using our ordinary technique, attempts were made to isolate B. pullorum from the yolks. The results were negative. A second experiment in which 12 eggs were used and immersed in culture for 30 minutes, likewise gave negative results when yolks and albumin were cultured. (d) B. Pullorum—Gas Production. Rice (9) states that a strain of B. pullorum may develop or lose gas producing power during cultivation. Strains of B. pullorum isolated from chicks in our laboratory are subjected to the various laboratory tests including their ability to ferment carbohydrates with gas formation. Before being used for any experimental work they are again subjected to the various tests. We have noted that strains, aerogenic when freshly isolated may, after several subcultures, become anaerogenic. Seven cultures were aerogenic when freshly isolated : when tested four months later, all had lost the power of producing gas through producing acid in glucose. It would appear there there is no necessity to describe two types of B. pullorum (A and B). Absorption of Agglutinins.—We first tested emulsions of B. pullorum and B. gallin arum with their respective agglutinating sera and also carried out cross agglutination tests, and found that the end points of the sera were identical ; we then carried out absorption tests to see, if by such means, the two organisms can be differentiated. A heavy emulsion of B. pullorum, grown on agar and washed off in