166 Flow to obtain it. 
an accessory hatchery, and in addition to this there are several 
excellent springs on the estate that have not as yet been used 
at all. 
I was obliged to sacrifice the Troutdale hatchery and ponds 
in Cumberland owing to the shortness of the water supply, and 
would warn others against falling into the same trap. Fish culture 
in those days was on a much smaller scale than it is now, and the 
prices of ova and fish much higher. Without an efficient water 
supply cultivation on anything like a paying scale is quite hopeless. 
There should at all times be enough, and plenty to spare, so that 
in any emergency there is an ample supply to fall back upon. 
Through a box containing twenty thousand ova, from five to ten 
gallons a minute should be used, and this will do for a set of five 
or six of such boxes. The quantity of water is increased as the 
hatching time approaches, and after hatching, fifteen gallons a 
minute are sometimes run through each box. 
I have already briefly traced the development of the embryo 
up to the formation of the chorda dorsalis or notochord. When 
about half incubated the two eye spots will become clearly visible, 
and as soon as they are fairly well developed the ova will bear 
handling, and an egg at this stage is a most interesting object 
when viewed under the microscope. The circulation of the blood 
can be distinctly seen as it courses along the chief arteries and 
some of the veins, in its passage to and from the heart, the 
pulsation of which may also be detected. The future skeleton of 
the fish may be traced, as well as the muscular fibre and tissues 
of the body, and from this day forward the whole presents an 
increasingly interesting object, the developing progress of which 
may be watched daily. Possibly during the first examination the 
tail of the fish may be seen to be possessed of a free movement. 
If not, it soon will be, and the deepening of the colour of the 
blood will also be observed about the same time. 
The accompanying figure represents the ovum of a trout in a 
forward state, as viewed under the microscope. Owing to the 
position in which it is placed only one eye (1) is in focus. The 
breathing apparatus or gills (2) are very distinctly seen, whilst the 
heart (7) may also be detected and the pulsations distinctly noted, 
although, being a little out of focus it does not show out as clearly 
