Modes op rsFBCTiON. 19 



the pasture, which favor infection of the disease. Con- 

 sequently detailed investigations have been carried out 

 along the following four lines, namely: 1. Infectivity 

 of the patients' excretion; 2. Infection through the 

 alimentary canal; 3. Infection in the stable and; 4. Infec- 

 tion in natural environment. Towards the solution of 

 the above problems the Committee has devoted most of 

 its energy and time extending over six whole years. 

 The number of the horses used for these experiments 

 reached about 150. 



A. Infectivity of the Patients' Excretion. 



1. Urine.— Two horses received subcutaneously 100 

 c.c. of the patient's urine and one other horse 150 c.c. 

 After latent periods of 11-17 days all three became af- 

 fected. Three horses received subcutaneously 15 c.c. of 

 a patient's urine. They showed typical symptoms after 

 15-25 days (Experimental horses-extra series Nos. 2, 3, 31). 



2. Faeces.— Faeces of a patient were mixed with 

 saline solution and were treated with Berkefeld's filter. 

 The filtrate was injected into a horse without any effect 

 whatever. Hence we may be able to conclude that the 

 virus passes out in urine but not in faeces. This result 

 agrees well with that obtained by feeding experiments 

 to be described in the next section. 



B. Infection through the Alimentary Canal. 



100-200 c.c. of the patient's urine was given every 

 day internally to two horses (Experimental horses-extra 

 series Nos. 34. 47). All became affected in a little over 

 thirty days. One horse (Experimental horse No. 479) re- 



