64 A MANUAL OF PHYSIOLOGY 



D, D', E, E', F, F'. Save the rest of the heated sera for (8). There 

 is no laking in any of the tubes, but probably agglutination in D, D', 

 and E, E'. (The complement is destroyed, but not the intermediary 

 body or amboceptor, or the agglutinin -p. 27.) 



(7) Put half of the contents of tubes D, D', E, E', into four separate 

 test-tubes, and, add to each o'2 c.c. of rabbit's serum. If there is 

 laking now it is because the rabbit's serum contains complement. 

 Save the balance of D, D', E and E' for (8). 



(8) Allow o'5 c.c. of ox serum to act at o C. on the rabbit's 

 washed corpuscles contained in 5 c.c. of the 5 per cent, suspension 

 after removal of the sodium chloride solution. The ox serum and 

 rabbit's corpuscles are separately cooled to o C. before being mixed, 

 and the mixture is then kept at o C. for one hour. Centrifugalize the 

 serum off rapidly. Label it ' Serum S.' To o'2 c.c. of the original 



5 per cent, suspension of rabbit's washed corpuscles add o - 1 c.c. of 

 this serum (labelling the tube G), and put at 40 C. with a control-tube 

 containing the same amount of suspension plus salt solution instead 

 of serum. Add the rest of the serum S, cooled to o C., to the same 

 cooled rabbit's corpuscles, and leave for a further period at o C. 

 Then centrifugalize rapidly, and to o'2 c.c. of the original suspension 

 of washed rabbit's corpuscles add 0*1 c.c. of serum S (labelling the 

 tube H), and put at 40 C. with a sodium chloride tube as control. 

 There may be no laking in either G or H, or if there is laking it may 

 be greater in G than in H. The amboceptor has been removed 

 from serum S by the rabbit's corpuscles. Add 0*1 c.c. of this ' in- 

 activated ' serum to the balance of D, D', and E, E 7 (left from 6). 

 Laking will occur because the serum S contains complement, and the 

 heated serum added in (6) to these tubes contains amboceptor. 

 Wash the rabbit's corpuscles which have been treated with ox serum 

 at o C. with cooled sodium chloride solution. Add to them some of 

 serum S (that from the top of tube H will do if no more is left), and 

 put at 40 C. Laking will occur, showing that the amboceptor was 

 fixed by the rabbit's corpuscles at o C. To a further portion of 

 the washed rabbit's corpuscles which were treated with ox serum at 

 o C. add normal rabbit's serum, and put at 40 C. If laking occurs 

 it is because the rabbit's serum contains complement. 



Dog's serum may be used instead of ox serum for experiment (8). 



13. Osmotic Resistance of the Coloured Corpuscles. Fill a burette 

 with a i per cent, solution of sodium chloride and another with dis- 

 tilled water. Take a series of ten test-tubes and run into the first 



6 c.c. of the NaCl solution, into the second 5*8 c.c., into the third 

 5*6 c.c., and so on, always making a difference of 0*2 c.c. between 

 each two successive test-tubes. From the other burette run in 

 enough distilled water to make up 10 c.c. of solution in each tube 

 that is, 4 c.c. of distilled water for the first tube, 4*2 c.c. for the second, 

 and so on. Shake up. The tubes now contain a series of solutions 

 of salt differing in strength by 0*02 per cent, in successive tubes, the 

 strongest being o - 6 per cent., and the weakest 0^42 per cent. Number 

 the tubes i to 10, beginning with the strongest solution. Put into 

 each tube one drop of perfectly fresh blood. Shake moderately so as 

 to mix the blood and salt solution, and allow the tubes to stand for 

 ten to thirty minutes. Observe the colour of the clear liquid above 

 the sediment of corpuscles. Determine in which tube the first tinge 

 of haemoglobin appears. The next higher concentration of the salt 

 solution is that in which all the corpuscles are just able to retain their 

 haemoglobin, and is a measure of the minimum osmotic resistance 



