50 



SOLID MEDIA 



5. A second assistant hands the sterile bottle, loosens and removes the 

 outer covering, and perforates the inner cover with the glass tube attached 

 to the rubber tube. Now release the pressure on the rubber tubing, and 

 blood will flow into the bottle. 



When the first bottle is three-parts filled, stop the flow of blood by pinching 

 the rubber tubing ; the assistant then withdraws the glass tubing from the 

 bottle and covers the mouth as quickly as possible with the paper cap and 

 fastens it round the neck. Fill a second bottle in the same way. 



5 to 6 litres of blood can be taken from an horse without harm, but 3 litres 

 is sufficient to take from a young heifer. 



6. Place the bottles in a cool place for 36 hours. The serum, which is 

 transparent and of a beautiful pale yellow colour, will then be floating on 

 the surface. Decant the serum from the clot with a Chamberland flask [or 

 Cobbett's bulb], being careful not to contaminate it, and distribute it at once 

 in sterile tubes as described above (pp. 45 and 47). 



C. Latapie's apparatus. Recommended. The technique of Eoux and 

 Nocard's method is simplified by using this apparatus. All contamination 

 is avoided, and a yield of about 700 c.c. of serum per 

 litre of blood is obtained instead of 400-450 c.c. by the 

 ordinary method. 



Description. The apparatus (fig. 40) consists of a 

 wide-mouthed bottle F capable of holding several 

 litres, and plugged with an india-rubber plug B per- 

 forated with three holes. A number of glass tubes (t) 

 open at both ends and perforated with several holes 

 laterally, is put into the bottle. Three pieces of glass 

 tubing are passed through the india-rubber plug. 

 Through one (a) the blood enters the bottle, a piece 

 of rubber tubing connecting it with the cannula. The 

 tube b is simply to allow access of air to the interior ; 

 it is plugged above with wool, while the other end 

 extends some distance into the bottle and is bent in 

 the form of an U. Lastly, the tube e serves for the 

 collection of the serum : its lower end also bent in an 

 U -shape reaches a few cm. below the plug, while its 

 upper end is attached by means of a piece of rubber 

 tubing to a piece of glass tube drawn out and sealed 

 in the flame. A clip can be placed on the rubber con- 

 nexion p to disconnect the two pieces of glass tubing. Finally, the apparatus 

 is arranged in a special support (not pictured in the figure) which allows 

 the bottle to be inclined so that the neck points upwards or downwards 

 at will. 1 



Technique. 1. Sterilize the apparatus in the autoclave. Moisten the 

 wool in the tube 6, wrap the bottle in filter paper, and raise the temperature 

 slowly. After sterilization allow to cool, and then lute the plug with paraffin. 



2. Puncture the vein as in Roux and Nocard's method, and connect the 

 cannula to the tube a. The bottle must not be more than half-filled and 

 the blood must not reach to the level of the air tube b. The flow of blood is 

 stopped by clipping the tube a. (The bottle is of course held with the neck 

 up during this part of the operation.) 



3. Leave for 12 hours or more until the blood has clotted. 



FIG. 40. Latapie's ap- 

 paratus, in which to collect 

 blood for serum from large 

 animals (horse or bovine). 



1 In Chapter XII. an apparatus, designed by the same observer, for the collection of blood 

 from small animals will be described. 



