19 



are best made of metal, and for this purpose nickel (or Gor- 

 man silver) is preferable, as being less liable to rust. A col- 

 lector should have two sizes, as a large size is not convenient 

 for small eggs, and a small one causes loss of time in blowing 

 large eggs. They should be made as light as possible, or they 

 may slip from the mouth and break the egg being operated on. 

 The chief point to be attended to in their construction, is that 

 the lower orifice should be as large as the size of the pipe per- 

 mits. It is of course necessary that they should be perfectly 

 smooth outside, towards the lower end. They may be straight, 

 although the curve is preferable. 



Fig. 6 represents a tube for emptying small eggs by suction. 

 The bulb is to receive tl»e contents of the ^'^g and prevent them 

 from reaching the mouth of the operator and thus causing 

 nausea. This instrument is best made of thin glass, as thereby 

 it can be easily kept clean. The same remark applies to this as 

 to the last, with respect to the size of the lower orifice. 



N. B. A piece of thin wire {fig. 6*), long enough to pass 

 entirely through the tubes, should be always kept at hand by 

 the operator, to remove obstructions which are likely to occur 

 from small pieces of the embryo, or half-dried yelk, being acci- 

 dentally drawn into the tubes or blowpipes. 



Fig. 7 represents a syringe, which will be found useful in 

 rinsing out the inside of an egg. It may be made of any metal, 

 though the pewter ones are apt, from their weight, to be clumsy. 

 Nickel is recommended, as for the common blowpipes. The 

 lower orifice should be as large as possible. The ring at the 

 top should be large enough for the insertion of the operator's 

 right thumb — as it must be remembered that he has to work it 

 rtith one hand. The nozzle, as shown in the figure, is rather 

 too tapering. It should be smaller in proportion at the upper 

 end. 



Figs. 8 and 9 represent scissors of shapes likely to be found 

 very useful. Fig. 8 for cutting through the bones of the embryo 

 hefore it is extracted, aud fig. 9, for cutting off portions of it, 

 tchile it is being extracted by one of the hooks represented in — 



Figs. 10, 11, and 12, which should vary in size from that of 

 an ordinary pin to that of stout wire. The len^h of their 

 straight portions should be rather more than the diameter of the 

 egg they are used on. 



