CRYSTALLOIDS OF BLOOD 



239 



the most varied conditions. As we have seen, this is due in great 

 part to the salt- and water-holding power of the colloidal con- 

 stituents, especially of the globulins. Bunge, in his handbook of 

 physiological and pathological chemistry (1889), suggested that 

 as the notochord and branchial clefts were legacies from fore- 

 bears who had lived in the sea, the high sodium chloride content 

 of mammalian blood might also be an heirloom from marine 

 ancestors. No doubt the circulation fluid of marine animals 

 with an open coelomic system is sea water. It is held by many 

 observers, that when the ancestral form of vertebrates acquired 

 a closed form of circulatory system, the fluid shut in was sea water. 

 Analysis shows that while the concentrations of crystalloids in 

 plasma and in sea water are not similar, yet there is a remarkable 

 resemblance in the proportions of the main salts present in both. 



Na K Ca Mg 



Serum (defibrinated plasma) 100 6-69 2-58 0-8 



Ocean - 100 3-66 3-84 11-99 



TABLE XXXII. 

 Non-clotting Blood. 



The similarity in proportion is not very striking because the 

 figures given are from analysis of the ocean as it is to-day. What 



