H. P. WOLVEKAMP 



in the physico-chemical properties of the blood, due to manipulations 

 during the experiment, because the phenomenon is reversible (Figure 2). 



80 90 



Figure 2. Abnormal Bohr effect in the 

 blood of the edible snail (Wolvekamp 

 and Kersten*). I — Dissociation curve 

 in the virtual absence of C0 2 . // — at a 

 C0 2 pressure of 23 mm. Ill — in the 

 virtual absence of C0 2 . The blood 

 sample previously used for the deter- 

 mination of curve II was evacuated and 

 used for obtaining curve III. 



It is a typical pB. effect because identical dissociation curves are obtained 

 after addition of dilute hydrochloric acid instead of carbon dioxide, 

 provided the pH values are the same 4 . Now this fact according to 

 current notions on the significance of the s-shape, ought to make this 

 animal one of the most unhappy representatives of the animal kingdom 

 because not only the discharge of oxygen into the tissues is interfered 

 with but the acquisition of oxygen in the so-called lung, in which 

 according to M. A. IJsseling 8 carbon dioxide tension may rise to 

 relatively high values, especially during hibernation, must needs be 

 lowered as well. 



The oxygen dissociation curves of the blood of several decapod 

 Crustacea have been determined as long ago as 1926 by Stedman and 

 Stedman 1 and by Redfield, Coolidge and Hurd 1 . They are all steep, and 

 occupy a similar though not identical position. Recently I have per- 

 formed some experiments on the influence of temperature and pH on 

 the oxygen binding of blood of lobster and crab. Previously, similar 

 experiments on purified solutions of haemocyanin have been performed 

 by Stedman and Stedman 1 and by Redfield and Ingalls 1 . 



The blood of the lobster (Homarus vulgaris M.E.) shows two 

 peculiarities. In the first place at higher temperatures the inflection of 

 the dissociation curve is much more marked. This, combined with 

 the customary shift of the whole curve to the right, will greatly enhance 

 the discharge of oxygen into the tissues at higher temperatures, a fact 



304 



