264 BOYINE OBSTETEICS 



difficult and fatiguing task. In most cases one person suffices 

 to extract the various parts of the calf. The force which he 

 exerts amounts to about 100 kg. 



Whatever has once heen started must be finished. Anybody 

 not immediately successful when performing embryotomy must 

 beware of cutting here and there. A regular course must 

 be followed ; for instance, when a fore leg breaks off at the 

 elbow joint one must not start to remove the other fore leg, 

 leaving the humerus and scapula of the former one. It 

 matters not how tedious and painful the task, anything we 

 once conclude to remove must be entirely removed and no half 

 work permitted. 



Anybody living up to these rules becomes an expert ob- 

 stetrician in due time; but anybody changing his system 

 constantly never becomes competent. 



2. — The Instruments for Embryotomy. 



As the historical review shows, certain cutting instru- 

 ments have been employed early to remove parts of the calf. 

 Thus Giinther describes a curved finger knife and a sliding 

 bistoury. Both are still to-day very useful instruments. 



A knife which I use frequently is seen in figure 46. 

 Franck-Goring termed it a modified finger knife of the Vienna 

 collection. 



Fig. 46.— Finger Knife. 



Pig. 47 shows Giinther's sliding bistoury; by sliding the 

 knob backward, the knife can be introduced within the handle. 



Karl's embryotome is a finger knife with a cross-piece. 

 The latter has such a shape that one end rests between the 

 thumb and index finger, the other upon the little finger. 



A useful finger knife is shown in fig. 48. 



