CULTIVATION OF THE TURBOT. 



867 



I thought it advisable to make a few modifications in the apparatus of 

 Fabre-Domergue and Bietrix which seemed to me of great importance to the 

 final success. On the thread of the vertical rod carrying the disk I attached 

 above the level of the water, as tightly as possible, a small wad of absorbent 

 cotton to take up and keep off the oil that might come from the wheels above it. 

 I had observed that a small part of the oil could descend along this vertical 

 glass rod and thus reach the water, where it formed a thin layer, the effect of 

 which was hindrance of aeration, causing asphyxiation of the larvae. Below this 

 wad I placed, upside down, the disk-shaped cover of a small vessel, thus to keep 

 dust from falling into the water, without, however, 

 hindering the circulation of the air. This disk was 

 secured below by a second wad of cotton. I also 

 utilized the lower, lateral, tubular outlet of the 

 barrel to set up a tube within terminating at the 

 top in a funnel covered with very fine silk, to allow 

 the passage of water but not of larvae. The open- 

 ing of this funnel was the size of a 5-franc piece, 

 and the flare thus obtained was designed to 

 decrease, as far as possible, the intensity of the 

 current, which, were it too violent, would cer- 

 tainly have carried the larvae with it. This pos- 

 sible carrying out of the larvae constitutes a real 

 danger, against which, however, we are still better 

 protected in the apparatus which we have had 

 constructed for our experiments in 1908. 



Several times a day part of the water in the 

 barrel was renewed for 10 minutes by means of a 

 siphon, there being in the course of the supply 

 tube a flaring inlet for the purpose of aeration. 

 Several times a day also the bottoms of the basins were carefully siphoned 

 to remove the dead eggs and all other matter that might pollute the water. 

 These modifications, of details only, which we have made in the excellent 

 apparatus in which Fabre-Domergue and Bietrix have been able to carry the 

 sole past the critical stage ought to be considered an indication, so to speak, 

 of more important modifications which will render possible its practical use 

 on a larger scale than from the point of view of experiments only. 



The hatching of the eggs took place without difficulty and without hindrance 

 between the sixth and eighth days after spawning. Two or three days after the 

 appearance of the larvae, without waiting for the complete absorption of the 



Fig. 2. — Apparatus for hatching turbot 

 (modi6cation of apparatus of Fabre- 

 Domergue and Bietrix), a and 6, wads of 

 cotton ; c. upturned cover which serves as 

 dust shield; tf. inflow pipe- e. outflow pipe 

 with screened funnel entrance; /, revolv- 

 ing disk for agitation of the water. 



