Collected papers . = t, 100 2-000 — 3 61-4 1-788 •071 6 34-8 1-542 •076 9 24-9 1-396 -067 mean -074 5 70-4 0=f., 100 2-000 — 2 52-5 1-720 -16 4 25-3 1-404 -15 6 14-1 1-J50 -15 7-5 7-6 •886 •15 mean -15 * Time was reckoned from the taking of the first sample, from a time when thetemperature of tube and contents was known to have reached that of the bath. 410 H, CHICK AND C. J. MARTIN. In the right-hand column of the table are given values for thevelocity constant, calculated on the assumption that the process proceedslogarithmically. These are in good agreement, indicating that thereaction
Collected papers . = t, 100 2-000 — 3 61-4 1-788 •071 6 34-8 1-542 •076 9 24-9 1-396 -067 mean -074 5 70-4 0=f., 100 2-000 — 2 52-5 1-720 -16 4 25-3 1-404 -15 6 14-1 1-J50 -15 7-5 7-6 •886 •15 mean -15 * Time was reckoned from the taking of the first sample, from a time when thetemperature of tube and contents was known to have reached that of the bath. 410 H, CHICK AND C. J. MARTIN. In the right-hand column of the table are given values for thevelocity constant, calculated on the assumption that the process proceedslogarithmically. These are in good agreement, indicating that thereaction velocity at any moment is proportional to the concentration ofunchanged haemoglobin. This is graphically shown in Fig. 2, wherelogarithms of haemoglobin-concentration are plotted against time, andfive straight lines are obtained corresponding to the five experimentsin Table I. As the temperature is raised, these lines become rapidlysteeper, and the velocity constants in Table I become greater in io ito so (,0 10 80 90 100 Fig. 2. Coagulation of hsBmoglobin in 3 % solution at temperatures from 60° C. to 70° C.(original concentration = 100). Ordinates = logarithms of concentration of haemoglobin. From the results of these experiments it is evident that the changeoccurring on heating a solution of haemoglobin is a reaction of the firstorder. Our interpretation of the facts is as follows : Water reacts withhaemoglobin, and this reaction results in the splitting off of haematin and fi HEAT COAGULATION OF PHOTE/NS. 411 the formation of an insoluble protein. As the water is in infiniteexcess, at any one temperature the rate of reaction is determined onlyby the residual concentration of the haemoglobin. At ordinary tempera-tures this reaction between haemoglobin and water is inappreciable, butis greatly enhanced by raising the temperature, in other words thereaction has a high temperature coefficient. This has been determinedfor coagulation of haemoglobin and egg
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