30 



Fourth — And last but not least, it entails a great deal of 

 expense. 



The results of such artificial feeding are found not to cor- 

 respond to its cost, and this fact deters many people from 

 engaging in the rearing of fish who would otherwise do so. 

 All the results of artificial feeding are based more or less on 

 hypothesis, because in making experiments the natural food, 

 both animal and vegetable, has in most cases nowhere been 

 investigated or taken into account. Now, I am sure no one 

 will deny that it is better, if possible, to stick to the natural 

 food, and give the powerful productions of nature a chance of 

 exercising their beneficial influence. What I wish to bring 

 before your immediate notice is this: '"That at a compara- 

 tively small cost, conditions closely approximating those of 

 nature can be established, under which conditions various forms 

 of natural fish food will live, thrive and multiply, so as to afford 

 a continual increasing supply of nutriment to the fish." 



For the past two years I have been making investigations 

 to find if possible some means by which fish, confined in small 

 ponds could be supplied with natural food. My first step was 

 to find out what the fish fed upon, and this led me to examine 

 the stomach contents of numerous fish during the different sea- 

 sons of the year. I confined my investigations to that most 

 interesting class — the salmonidse {Salvw fontinalis and Salmo 

 irideus). What may be termed a post-mortem examination 

 was performed — slitting the fish along its ventral or belly 

 aspect, thus exposing the alimentary tract, I tied two ligatures, 

 one around the gullet, the other round the intestine near the 

 pyloric, or lesser end of the stomach. Removing the portion 

 between the two hgatures, I opened the stomach and extracted 

 the contents, placing them on a white plate. These I examined 

 both by aid of the naked eye and microscope, then deposited 

 them in a glass vial containing rectified spirits, and afiixed a 

 seal and label indicating the kind of food and date of examina- 

 tion. Thus at the end of the season I had quite an array of 

 bottles containing different species of natural fish food. 



The majority of the food belonged to the invertebrate type, 

 including various species of Crustacea, insecta, worms, leeches, 



