64 IMMUNITY IN HEALTH 



the attempt was made on one occasion. I suspect these 

 bacteria may be associated with the cellulose-spUtting 

 process which must proceed on a large scale in the 

 rabbit's intestine. A good way in the rabbit therefore 

 is to stain the tissues fairly deeply with eosin and then 

 stain by Gram's method (taking care not to over- 

 decolourise) and mount in xylol balsam. Pappen- 



FiG. 29. 



From a photograph of bacilli in the lymphoid tissue of a healthy 

 rabbit's appendix. (Carbol-fuchsin decolourised in clove oil; 1/12 in. 

 objective.) 



heimer's pyronin and methyl green and Powell-White's 

 eosin and totuidin blue may be used, but have not 

 proved so satisfactory in my hands. Dr. Ruffer em- 

 ployed alum-carmine and Gram's method and was thus 

 able to demonstrate clearly the nuclei as well as the 

 bacteria in the glandular lymphocytes. 



It is because the bacteria in the rabbit's intestine 



