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EXPERIMENTAL PHYSIOLOGY. 



traction on the ligature and by bending the free end of the probe out through the 

 wound the duct and encircling mucosa is brought out to the skin, care being taken 

 not to stretch or twist the duct. The edges of the mucous circle are now stitched 

 by a fine silk or chromacised catgut ligature to the edges of the skin wound. The 

 wound in the mouth is similarly stitched and without the application of any 

 dressing the animal is allowed to come out of the anaesthetic. The wound should 

 be bathed daily with physiological saline and a free secretion of saliva occasionally 

 stimulated by giving the animal some dry food (bread crumbs). 



When the wound has healed, it will be necessary to accustom the dog to being 

 strapped into a suitable holder and it is most important for the success of the 



FIG. 67. Funnel applied to skin of animal for collection of fistula juices. (Pavlov). 



observations that the animal should be trained to submit to the harnessing 

 without fear or excitement. The knowledge that feeding is to follow soon makes 

 the animals eager to participate in the proceedings. To collect the secretion 

 Pavlov uses a funnel, made out of wax and resin* with its edges flared out so as to 

 form a flat surface to apply to the skin (Fig. 67). To apply the funnel the hair 

 around the duct is clipped close by a scissors and thoroughly dried. The funnel 

 is then moderately warmed and the flared edge firmly pressed on the cheek to 

 which it adheres, after which the narrow end is attached to a light graduated test- 

 tube. In removing the funnel care must be taken not to abrade the skin. Holding 

 a warmed metal rod near the edges helps to loosen the attachment to the skin 

 *50 parts, rosin ; 40 parts, ferric oxide Fe2Os and 25 parts yellow wax. 



