i74 



Appendices to Fourth Annual Report 



In addition to these I have found : — 



(/.) It is a proteid of the globulin class. This is shown by the fol- 

 lowing facts : — 



(i.) It is precipitated by dialysing out the salts from the 

 serum. 



(ii.) It is completely but slowly precipitated by saturation 

 with magnesium sulphate, completely and rapidly by 

 saturation with sodio-magnesic sulphate, and incom- 

 pletely by saturation with sodium chloride, 

 (m.) It is incompletely precipitated in dilute solutions by 

 weak acetic acid, or by a stream of carbonic acid. 

 [g.) It takes no part in the formation of the clot. Addition of fibrin 

 ferment to a solution of pure hsemocyanin does not cause the 

 formation of fibrin. Crustacean fibrin, moreover, contains no 

 copper. 



(/?.) The temperature of heat coagulation I place at a rather lower 

 point than that hitherto given, viz., 65° c. 

 2. Crustacean fibrinogen. — All the proteid matter in the salted plasma 

 coagulates as in the serum at 65° c. Hence it is not possible to separate 

 crustacean fibrinogen from hsemocyanin by a method of fractional heat 

 coagulation. 



It is precipitable by means of dialysis or saturation with various salts. 

 Hence it, too, like hsemocyanin is a globulin. It, however, difi'ers from 

 haemocyanin in its behaviour to one salt, viz., sodium chloride. It is 

 completely precipitated from its solutions by saturating them with that 

 salt. This furnishes us with a method of separating the two proteids. 

 After shaking the plasma with sodium chloride for about three hours, a 

 precipitate of proteid material is obtained. This consists of hiemocyanin 

 and fibrinogen mixed together. This is collected on a filter, and the 

 hsemocyanin can be washed away by saturated solution of sodium chloride, 

 leaving the fibrinogen undissolved on the filter. On the addition of dis- 

 tilled water to this it dissolves, being enabled to do so by the salt adher- 

 ing to it. A somewhat opalescent but colourless solution is thus 

 obtained. On the addition of fibrin ferment to it, fibrin is formed. 



Part IV. — Colouring Matters of the Blood. 



These are two in number. 



1. The blue colour associated with the proteid hsemocyanin. 



2. Traces of a red pigment, tetronerythrin. 



1. Haemocyanin has already been treated of in the preceding part of 

 this paper. The blue colour is due to the combination of oxygen with it. 

 This occurs, as was first shown by Fredericq, not only in experiments with 

 haemocyanin outside the body, but also in the body itself; the blood 

 going to the gills being colourless, and that leaving them having a blue 

 colour. 



There can be no doubt that haemocyanin plays a part analogous to 

 that of haemoglobin in vertebrate animals ; that is, it is the oxygen carrier. 

 It is not, however, located as haemoglobin in vertebrates is, in special 

 corpuscles, but exists in solution in the blood plasma, as haemoglobin 

 itself does in the blood of many worms. 



Haemocyanin has been described as occuring in all decapod and other 

 thoracostracous Crustacea whose blood has been examined. While among 

 the malacostracous Crustacea, its place is taken by haemoglobin, which is 

 dissolved in the plasma as in the worms just alluded to. 



