6 4 



THE CIRCULATING LIQUIDS OF THE BODY 



another set of five small samples, and at as long an interval as possible 

 thereafter five more. Now letting the dog bleed to death, observe that 

 the flow of blood is temporarily increased by pressure on the abdominal 

 walls, which squeezes it towards the heart, by passive movements of 

 the hind-legs, and also during the convulsions of asphyxia, which soon 

 appear. Add to the peptone blood D 5 c.c. of serum, to E a little 

 sodium chloride extract of liver, to F a little extract of muscle, and to 

 G 15 drops of a 2 per cent, solution of calcium chloride, and put C, D, 

 E, F, and G into a water-bath at 40 C. Treat the other sets of small 



samples in the same way. Note 

 how long each specimen takes to 

 clot, and report your results.* 



(8) Observe that the blood in a, 

 8, and y has not coagulated. Label 

 four test-tubes ' Oxalate A, B, C, 

 D,' and put into each about 5 c.c. 

 of the oxalated blood. Add to A 

 and B 5 or 6 drops of a 2 per cent, 

 solution of calcium chloride, to C 12 

 drops, and to D as much as there 

 is of the blood. Leave A at the 

 ordinary temperature, put the other 

 test-tubes in a water-bath at 40 C., 

 and note when clotting occurs. 



(9) To 10 c.c. of the fluoride blood 

 add a little more CaCl 2 than is re- 

 quired to combine with the excess 

 of fluoride present. Label four test- 

 tubes ' Fluoride A, B, C, D,' and 

 into each put about 2 c.c. of this 

 ' recalcified ' fluoride blood. To B 

 add i c.c. liver extract, to C i c.c. 

 muscle extract, and to D 4 c.c. 

 water. Label two more test-tubes 

 ' Fluoride E and F.' Into each put 

 2 c.c. of the fluoride blood without 

 CaCl a . Add also to E i c.c. liver 

 extract and to F i c.c. serum. Put 

 all the tubes in a bath at about 

 40 C., and observe in which and in 

 what time coagulation takes place. 



(10) By means of a centrifuge 

 (Fig. 17) separate the plasma from 

 the corpuscles in a, /3, and 7, and 

 also from the peptone blood. 



With the oxalate plasma from /3, 



and the fluoride plasma from y, repeat the observations in (8) and 

 (9), using smaller quantities of the plasma, if necessary, in small test- 

 tubes. With the plasma from a perform the following experiments : 

 Put a small quantity of the plasma (i c.c.) into four test-tubes, labelling 



* Sometimes the injection of peptone hastens coagulation instead of hinder- 

 ing it. It has been asserted that this is only the case when small doses are 

 used (less than 0-02 gramme per kilo of body- weight) . But in 2 dogs out of 

 ii a dose of 0-5 gramme per kilo has been seen to hasten coagulation, and in 

 i out of 12 to leave it unaffected; in the other 9 coagulation was markedly 

 retarded 



Fig. 17. Centrifuge (Jung). The four 

 cylinders shown at the top of the 

 figure are so swung that they become 

 horizontal as soon as speed is up. 



