152 KITAJIMA. 



I began the investigation upon which I am now reporting in the year 

 1902. A branch office of the Institute for Infectious Diseases was estab- 

 lished and a temporary laboratory erected at Amami, Oshima, where I 

 could have free access to the habu and so had facilities for collecting the 

 venom. Since the time of beginning the work I have purchased more 

 than G,000 serpents. Dr. Mine, my former assistant, helped me in 

 various portions of the research, and my present one, Yamamoto, is still 

 engaged in collecting the venom at Oshima. I desire here to express my 

 thanks for their collaboration and for the encouragement given by Profes- 

 sor Kitasato, director of the institute. 



THE "HABU" SNAKE. 



CEOTALINiE. 



Trimeresurus flavoviridis (Hallowell). 

 Trimeresurus riukiuanus (Hilgendorf ). 



The length varies from 1 to 1.5 meters; the snake has a large, triangular, flat 

 head which is separated from its spotted body by a distinctly marked neck. The 

 fang is tube shaped. An indentation's present at the back of the eye. 



The bites occur during the time from June to December, June and 

 July being most dangerous months. No bitten persons have been re- 

 ported in January and February. Eighty out of 174 cases were bitten 

 on their lower limbs, 39 on the upper, and a few on the head, face, body, 

 etc. It is dangerous to collect the venom, but finally in the laboratory 

 we encountered a very dexterous manipulator among our employees. 

 Even he would be bitten once or twice a year, but in the end the bites 

 produced only a slight reaction, as he gradually acquired an immunity 

 against the venom. 



The process of collecting venom adopted by us is as follows : One of the snakes 

 is taken out of the cage, its head quickly fixed with a forked stick, and as soon 

 as the serpent stretches out its body on the floor its neck is caught with one hand 

 and its mouth opened sufficiently to admit a watch glass, upon which the poison is 

 discharged by compression from outside the sack at position of the poison gland. . 

 In our experiments the poison collected from a number of snakes was used for 

 work. 



HABU VENOM. 

 THE PHYSICAL AND CHEMICAL CONSTITUTION OF THE VENOM. 



Venom collected from the habu is a viscous, slightly yellowish fluid 

 with an acid reaction, 0.6 cubic centimeter of a 0.01 normal alkali solu- 

 tion being needed to neutralize 1 cubic centimeter. The quantity dis- 

 charged at one time varies both with the size of the snake and the season 

 of the year; it ranges from 0.5 cubic centimeter to 1 cubic centimeter; 

 in rare cases it is 1.4. When the venom is centrifugated and the 



