518 PROCEEDINGS OF SECTION D. 



therefore, wlio have to fight against this insidious epizootic amongst 

 rats it is interesting, and sometimes exceedingly helpful, to study the-, 

 other diseases with which they may be affected. Suspicion has further 

 attached to them in regard to the transmission of trichina to pigs (and 

 thence to man), but it is needless to relate that this invasion has not 

 been met with in Western Australian rats. 



I wiJl not deal with plague further than to mention, as you all 

 know, that during each of the epidemics in man in the West it has 

 been found in epizootic form amongst the rats. 



Enlargement of the Spleen. — Again and again, but especially in the- 

 case of many of the rats on the wharves at Fremantle, a firm enlarge- 

 ment of the spleen — occasionally six to eight times that of the normal 

 organ — has been noticed. Occasionally the liver was also enlarged and 

 congested. Films, cultures, and inoculations in no instance have 

 thrown any light on the condition. Is it possible that it has any con- 

 nection with trypanosome infection, Avhich is so common ? 



Ulceration of Feet with Death. — Amongst the rats in captivity it 

 occasionally happens that cagefuls would mysteriously die off. At 

 last this was traced to ulceration of the soles of the feet, sw^arming with 

 organisms, with which was associated considerable oedema of the limbs. 

 The condition was traced to damp cages. 



DarJc Pigmentations of Lymphatic Glands. — Not infrequently lymph- 

 glands, not obviously enlarged, have been noticed with very dark pig- 

 mentation, as if from altered blood-pigment. Does this condition 

 indicate any previous h.iemorrhagic condition of the gland {e.g., plague) ? 



Chronic Abscesses. — These have been seen once or twice in the groin, 

 etc. Though the pus that they contained was examined for B. pestis, 

 it was not found. Inoculations were not made, however, and recent 

 work in India strongly suggests that they might have had their origin 

 in plague. 



Wartij Ears and Tail. — Quite a number of rats had the former con- 

 dition in a marked degree, and a good many the latter. The former 

 microscopically appeared papillomatous. We thought at one time the 

 condition was associated with numerous ova (of an oval form) packed 

 in the liver substance ; but later examples of warty ears without the 

 latter were met with. 



ANIMAL PARASITES OF RATS. 



Tamia sp. — A tapeworm has been met with occasionally in the 

 intestines. 



Cystic Stage of Trenia sp. in Liver. — Fairly frequently a minute 

 cyst containing a head and short neck has been encountered imbedded 

 in the surface of the liver. 



Round Worms in Stomach and Ova in Liver. — Round worms, like 

 small ascarides, are very frequently found in the stomach. In quite a 

 number of instances numerous ova, which correspond fairly closely 

 with the immature ova in the bodies of these worms, are found in the 



