PRELIMINARY REPORT ON THE TOXICITY OF COL- 

 LOIDAL SULPHUR TO FISH. 1 



By Chukichi Harukawa, Dr. Agr. (Tokyo Imperial University) 



Entomologist for the Ohara Institute 

 Karaschiki (Okayama), Japan 



INTRODUCTION. 



The present paper contains a part of the results of investiga- 

 tions which were primarily undertaken in connection with the 

 study of the toxicity of lime-sulphur mixtures. It has long been 

 known that sulphur powder is effective in controlling the mite and 

 certain fungi. Sabbatani (1) has shown that the action of colloidal 

 sulphur is more powerful than that of the other forms of sulphur. 

 These facts induced the writer to conduct some experiments to 

 learn the toxicity of colloidal sulphur to goldfish. 



Hydrogen sulphide dissolved in water has been known to 

 change to colloidal sulphur on slow oxidation. (Taylor 2.) It has 

 been reported that hydrogen sulphide develops in considerable 

 quantities in the Black Sea, in the Norwegian threshold fiords, and 

 in oyster pools of the Norwegian Coast, as well as various other 

 small sea basins. The statement is made that these oysters are 

 frequently killed by sulphur poisoning or lack of oxygen (Murray 

 and Hjort, 3). Hydrogen sulphide is also introduced into waters 

 by illuminating gas works and various industrial processes, such as 

 paper manufacture ( Shelf ord, 4.) In all these cases there would 

 be a zone of water in which hydrogen sulphide occurs in the pres- 

 ence of oxygen, so that there would probably occur a zone of water 

 containing colloidal sulphur. As will be seen later, the writer's ex- 

 periments have shown that colloidal sulphur is quite strikingly toxic 

 to goldfish. Hydrogen sulphide is also known to be toxic, but no 

 com.parisons have been made. Such comparisons would be made 

 with difficulty but it should be possible to determine the relative 

 toxicity of mixtures of the two and colloidal sulphur alone. 



Attention must, therefore, be called to the fact that hydrogen 

 sulphide is dangerous in the presence of oxygen, both on its own 



1 Contribution from tlie Zoological Laboratory of the University of Illinois, 

 No. 221. 



219 



