DISCUSSION. 519 



In Japan the incubation period of rabbits inoculated with street virus 

 is about two weeks at a minimum, but sometimes in other countries, 

 because of its weak virulence, we obtain the symptoms only in three to 

 six weeks after the inoculation, which of course must be subdural. The 

 result recorded in my table shows that the material was not contaminated 

 with other septic bacteria and the assumption is that this was a real case 

 of hydrophobia. 



In rabbit No. 127 the symptoms were slightly typical, so I took out 

 the brain, preserved it in sterilized glycerine solution and waited for 

 the appearance of the symptoms among the other two rabbits. The 

 second rabbit (No. 128) showed slight symptoms on the 30th of June 

 and these developed on July 1 (next morning) into the typical form 

 of this disease. The animal was nearly dead, when I chloroformed it 

 and took out the brain, preserved it in Zenker's fluid, for a pathological 

 examination by Doctors Ashburn and Craig. I injected the emulsion 

 of the medula oblongata into three other rabbits. The spinal cords of 

 both rabbits mentioned above I preserved in a vacuum to get material 

 for injection by the Pasteur method of immunization. 



I will now obtain the brain of the third rabbit and have smear exami- 

 nations made by Doctor^ A s hburn t and on the other hand, with this spinal 

 cord material, I will make inoculations into other rabbits. I have also 

 performed subdural inoculation with the preserved material from the 

 first rabbit. 



For a long time, the existence of hydrophobia in the Islands has been 

 under discussion and therefore we need perfect and exact investigation. 

 We need, further, experiment and observation to prove the existence of 

 this disease. Subdural inoculation must be made into a dog and the 

 symptoms developed must be watched. I will have the honor to report 

 as soon as my observations are completed. 

 Yours respectfully, 



Y. K. Ohno, 

 Assistant in the Biological Laboratory , Bureau of Science. 



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