98 



SEASON 1873-74. 



the eggs carefully ; they were all hill-burn trout eggs, and about 

 the same size. I then ordered a pipette to be made about 6 inches 



long, with a tube just large enough to 

 admit the ovum ; but the eggs, though 

 nearly, were not precisely the same 

 size, and one soon stuck in the tube. 

 For five minutes I was occupied with 

 my scarf-pin for the egg had gone a 

 couple of inches up before it jammed, 

 but to no purpose ; eventually I had 

 to remove the india-rubber and shove 

 it out with a straw. Next day I con- 

 sulted a very clever glass-blower, and 

 by the aid of a blowpipe we put a 

 constriction in the tube a quarter of an 

 inch from the end, and widened the 

 mouth to a like dimension (Fig. 41). 

 It answered well, and now all my ova- 

 extractors are made with tubes a quar- 



FIO. 4i-scaie \. FIG. 42- scale \. ter of an inch in diameter, inside 

 measurement, and a constriction a little less than a quarter of 

 an inch from the end (Fig. 42). The top of the bulb is covered 

 with india-rubber, so that it acts as a vacuum-chamber, and the 

 ovum is firmly held against the constriction at the end of the tube. 

 Old tobacco-pouches make the best covers for the ova-extractors. 



To use the extractor, the glass is grasped in the right hand, 

 the ball of the thumb presses on the india-rubber and expels a 

 small portion of air. The tube is then directed towards the dead 

 ovum it is not necessary to touch it, and by gently raising 

 the thumb the egg rises and rests in the cup without disturbing 

 any of the surrounding ova. The quickness some girls acquire is 

 marvellous. In the large hatching-house at Milnholme, sometimes 

 as many as 250,000 eggs have to be gone over for packing in one 

 day, and all the unimpregnated ova picked out ; and even where 

 the number is as high as 5 per cent., though this is unusual, two 

 girls can get over the work easily in a morning. 



