H. BARCROFT, Q. H. GIBSON and D. C. HARRISON 



difference in behaviour between the normal and pathological cells in 

 the presence and absence of glucose and lactate {Figure 4). The figure 

 shows the effect of adding these substrates to washed MHb-containing 

 red cell suspensions. Whereas the rate with normal cells is increased 

 about fivefold, scarcely any change takes place with cells from the cases. 

 Two minor points of some interest in connection with the coenzyme 

 factor I activity of the cells are the following. First, in the assay 

 experiments haemolysis increased the apparent activity very sub- 

 stantially, the activity per unit quantity of haemoglobin being about 

 six times the highest activity observed in intact cells. This difference 

 may be due to the close packing of the haemoglobin molecules in the 



Normals c ^es of Melhoe- 



moqlobinaemia 



Figure 3. The hatched rectangles 

 represent the results of assays of 

 coenzyme factor I in the blood of 

 twelve consecutive normal persons 

 and in five cases of methaemoglo- 

 binaemia. The last three cases 

 were patients described by Gibson 

 and Harrison (1947). The blood of 

 the last two cases contained con- 

 siderably less MHb than that of 

 the first three. 



Figure 4. Reduction of 

 MHb by erythrocytes 

 from a normal person 

 and from a case of 

 idiopathic methaemo- 

 globinaemia. The ordi- 

 nate gives the amount 

 of MHb reduced, ex- 

 pressed in H-l. CO 

 absorbed by 2-0 ml of a 

 cell suspension contain- 

 ing 15-6 g.J 100 ml total 

 pigments, incubated at 

 37°. The clear symbols 

 refer to the normal, the 

 shaded symbols to the 

 case. 



226 



