REPORT UPON A PARASITIC PROTOZOAN. 



189 



40. Cupric sulph. sol. (blue vitriol), 15 drops; 



lake water, 2,000 cc. 24-3°. 



41. Cupric sulphate, 1 cc; lake water, 200 cc. 

 3:36. Cup. sul., 1 cc. 



3:38. Cup. sul., 1 cc. 



42. 3 : 06. Potassium ferrocyanide, 1 per cent, 3 cc. ; 



lake water, 700 cc. 

 3:12. Pot. fer., 3 cc. 

 3:15. Pot. fer., 9 cc. 

 3:20. Pot. fer., 30 cc. 



43. 10: 24. Pepsin, 1 teaspoonful; lake water, 



1,000 cc. 

 10:35. Sat. salt sol., 5 cc. 

 10:50. Sat. salt sol., 5 cc. 

 2:30. Salt sol., 5 cc. 



Fish dies iu 7 minutes ; parasites unaffected. 



3:34. Small trout. 



3 : 42. Trout overcome ; revived in water. 

 3:56. Returned to solution. 

 4:10. Dead; parasites unaffected. 

 Trout lived 3 hours. Parasites unaffected. 



Trout died in 3 minutes. Parasites still alive. 



10:55. New trout. 



Trout overcome at 3 :00. Slime leaves fish to some 

 extent. Parasites unaffected. 



This experiment was tried with the hope of removing the slime from the fish by- 

 means of the pepsin, and thus reaching the parasites with the salt. The experiment 

 was repeated a number of times, but the results were extremely variable. 



44. Ichthyol, 7 drops ; lake water, 500 cc. 23-5° C. 



45. Ichthyol, 3 drops; lake water, 3,000 cc. 35° C. 



11:30. Ichthyol, 6 drops. 

 11:45. Ichthyol, 6 drops. 



12:01. Salt sol., 15 cc. 

 3: 16. Ichthyol, 9 drops; salt sol., 15 cc. 



46. Methyl violet, 2 cc. ; kerosene emulsion, 20 cc. ; 

 lake water, 2 L., 23° C. 



3:55. Catfish. 



4:32. Partially overcome and removed to fresh 

 water; parasites alive. 



9:55. Weak catfish. 

 10:30. Fish died. 

 11:07. Second catfish. 

 11 : 29. Parasites in water alive. 



12:00. Parasites in water alive. 



3:15. Parasites on fish alive; those in solution 

 dead. 



4:15. Second fish partially overcome; died in 

 fresh water; parasites on fish still alive, 

 (a) 11:23. Trout. 



11:44. Overcome; revived in water. 

 11:50. Returned to solution. 

 2:20. Dead; parasites on fish and many of 

 those in the solution are still alive. 

 (&) 2:25. Trout. 



3:45. Fish dies; parasites unaffected. 



It need hardly be stated that most of the above experiments were repeated two 

 or three times. When the result was similar and unsatisfactory on two or three dif- 

 ferent fish, the experiment was discontinued. 



