ARTIFICIAL PROPAGATION 195 



syphon tube, one end, which is cupped, being closed with india rubber, 

 will, by pressure of the thumb and sudden release of the pressure, suck 

 up into the tube any egg for closer examination. If the slightest trace 

 of white fungus is observed upon it, the egg should be at once destroyed, 

 for the fungus growth develops very rapidly if not checked Careful 

 charring of all wood used in the construction of the boxes, cleanliness 

 of all utensils, and careful examination of the eggs, are the best 

 preventatives against the disease appearing or spreading. 



A thermometer, several syphon tubes, two or three clear glass 

 wine-glasses, some enamelled cups, a tiny gauze landing-net, and a 

 bunch of seagull wing feathers should be always at hand. 



The only occasion for real anxiety at this period is during a spate, 

 when a large proportion of matter held in suspension in the water may 

 be expected to be deposited, if not on the eggs yet in the boxes. Of 

 course the best means to prevent this is careful filtration, first at the 

 source of supply, and again, if convenient, within the hatchery. But, 

 notwithstanding, the boxes will still require occasionally to be cleaned 

 while in service. This can be done without injury to the eggs, but, as 

 great care is necessar}- in the moving, cleaning wHth clear water and 

 replacing them, not to mention the cleaning of the boxes, it is a trouble- 

 some enough business. The danger of a deposit on the eggs is that it 

 prevents the free absorption of oxygen from the water through the shell 

 of the egg, and the free giving off of the carbonic acid gas generated 

 by the growth within, resulting in the suffocation and death of the 

 embryo. Periodical inspection should also be made at this time of the 

 intake chamber of the water supply, and the rose of the main pipe 

 should be examined to see that no floating matter has got in to foul it. 

 Decayed leaves are often troublesome in this respect. 



As presumably is also the case in nature some eggs will escape 

 fertilisation in the process of artificial propagation. They will very 

 soon turn a dead white colour. It is impossible to give any definitely 



