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Observations on Wild Rats in England 
(b) With similar infective material administered by the catheter (7 cases). 
2. Inunction experiments 
(a) With infective material through the skin without shaving the hair 
(4 cases). 
(b) With infective material through the shaved skin (1 case). 
These experiments were discontinued when the results of the work of 
Uhlenhuth and Zuelzer (1921) became available, as the hypothesis they 
advanced appeared a very reasonable one which was capable of explaining 
the vagaries of the disease. At the same time there are certain lines of investiga¬ 
tion which have not yet been followed and it may be possible to undertake 
them at a later date. 
It is scarcely necessary to give the results of this part of the investigation 
in detail. Only two positive results were obtained, both in catheter-fed animals. 
Each of these animals was given 1 c.c. of a saline suspension of the macerated 
kidneys of two guinea pigs which had died of infectious jaundice. One of the 
Chart 1. Eight-day temperature chart of guinea pig 79 ($), fed by catheter with emulsion of 
organs of infected guinea pig. Autopsy: typical of spirochaetal jaundice. 
Chart 2. Eleven-day temperature chart of guinea pig 81 (^), fed by catheter with emulsion of 
organs of infected guinea pig. Autopsy: typical. 
catheter-fed animals was killed 7 days, the other 10 days after injection, and 
both showed typical post-mortem appearances of the disease. During life 
both exhibited jaundice and an elevation of temperature (Charts 1 and 2) and 
in one case there was a characteristic and sudden fall coinciding with the 
termination of the malady (Chart 1). Had the animal not been killed it would 
have died within a short time. 
4. GENERAL PATHOLOGY. 
Pathological conditions, apart from those associated with helminthic and 
spirochaetal infection were rare. The kidney changes possibly associated wdth 
leptospira infection have already been mentioned by Stevenson. 
The other diseases encountered were pneumonia, cystic Fallopian tube, 
cystic kidney, cystic interstitial nephritis, vesical calculus, a condition in the 
spleen resembling actinomycosis, secondary septic infection of the lymphatic 
glands and various purulent infections of bacterial origin. 
