K. F. MEYER 635 



gorged spleens sometimes accompanied by exudations into the cavities have been 

 recorded. The pathogenicity of the epidemic strains is high and infections may be 

 secured by inhalation (Uchida).' Some strains are virulent for fowls, others are not. 

 Various forms of pseudotuberculosis and pneumonia (Keegan)^ due to diplo- 

 streptococci (Kutchera,^ Fricke) or Bad. bronchisepticum have been reported and 

 incompletely described. Bad. {Erysipelothrix) murisepticum is frequently the inciting 

 agent of highly destructive epidemics among migrating meadow and house mice 

 (Wayson).4 Mice are also the host of various intestinal flagellates (Trichomonas, 

 Giardia), which may favor certain intestinal infections (Smith and Tibbets).^ En- 

 cephalitozoon has been reported by Cowdry and Nicholson^ and Anigstein.' Klossiella 

 niuris is a common parasite and is not infrequently encountered in sections of the 

 kidneys (Bonne). ^ An excellent description of the life-cycle has been published by 

 Stevenson.' 



DISEASES OF RATS 



The maintenance of large rat colonies particularly for studies on nutrition has 

 aroused some interest in the communicable diseases of this rodent (Greenmann and 

 Dlihring,'" Hartwell, Mottram and Mottram"), although most researchers still re- 

 gard them as inevitable. Furthermore, the continuous struggle between man and the 

 rat and the important role of the latter in the transmission of disease has prompted 

 many valuable studies and publications on the infections of the wild rat and its 

 hybrid the albino. A summary will be found in a bulletin of the United States Public 

 Health Service entitled The Rat and Its Relation to the Public Health (1910) and in a 

 recent excellent review by Koehler (1925)." 



Respiratory infections frequently called "pneumonia" are more prevalent among 

 albino rats. Young animals are rarely affected while the mortality among the old 

 rats may be very high. In fact, all rats after reaching maturity may spontaneously 

 develop "lung disease." As a rule an acute stage marked by loss of appetite, dullness, 

 mucous nasal discharge, conjunctivitis, and a labored, unnatural, noisy breathing is 

 followed by a chronic stage during which the animals appear in a much depressed 

 state of health and finally succumb to the disease. At autopsy various stages of un- 

 resolved pneumonia, catarrhal bronchitis with voluminous bronchiectases, abscesses 

 of varying extent from a small mass to the almost complete obliteration of the lung 

 and pleural adhesions are nearly always observed. 



' Uchida, Y.: op. cit., 106, 303. 1926. ^ Keegan, J. J.: loc. cit. 



^ Kutchera, F.: Centralbl. f. Bakteriol., 46, 671. 1908. 



■• Wayson, N. E.: Pub. Health Rep., 42, 1491. 1927. 



5 Smith, T., and Tibbets, H. A. N.: loc. cit. 



^Cowdry, E. V., and Nicholson, F. M.: loc. cit. 



' Anigstein, L.: Compt. rend. Soc. de biol., 92, 991. 1925. 



''Bonne, C: ibid., p. iigo. 1925. 



'Stevenson, A. C: Quart. J. Micr. Sc, 61, 127. 1915-16. 



'"Greenmann, M. J., and Duhring, F. L.: Breeding and Care of the Albino Rat, p. 100. Phila- 

 delphia, 1923. 



" Hartwell, G. A., and Mottram, E. C, and V. H.: Biochem. J., 17, 208. 1923. 



"Koehler, G.: Zentralbl.f. d. ges. Hyg., 10, 161. 1925. 



