CONVERSION OF CHEMICAL ENERGY 



75 



2. Why do cells not mix with the liquid in contact with 

 them ? 



3. What exchanges take place between cells and extra- 

 cellular solutions ? 



4. How do changes in the surrounding media affect cells ? 

 These problems are of great importance because they apply 



to all kinds of cells whether they are those of unicellular or 

 multicellular organisms. The difference between unicellular 

 and multicellular organisms is that, as a rule, the media 

 surrounding the former are more variable whilst those sur- 

 rounding the latter are approximately uniform in composition 

 and there is a circulatory mechanism to renew the solution 

 surrounding the cells. 



CHEMICAL DIFFERENCES BETWEEN CELLS AND THEIR 

 SURROUNDINGS 



The chemical differences between cells and their surround- 

 ings vary with the kind of cells and the nature of their habitat. 

 A characteristic difference is that between red blood corpuscles 

 and the plasma in which they float. 



TABLE XIV 

 Showing Analysis of Horse's Blood* 



Contained in 1,000 parts of 



Constituent Serum Corpuscles 



Water 902-05 



Solids 97*95 



Proteins (not haemoglobin) 84-24 



Haemoglobin 



Sugar 1-176 



Cholesterin 0-298 



Lecithin 1-720 



Fat 1-300 



Phosphorus as nuclein 0-020 



Sodium 4*434 



Potassium 0-263 



Ferric oxide 



Calcium 0-1113 



Magnesium *45 



Chlorine 3 - 726 



Phosphoric Acid 0-240 



Inorganic Phosphoric Acid 0-0715 



TABLE XV 



Showing the difference between the composition of the unicellular 



plant Asterionella and the water in which it lives. -\ 

 As no analysis is given of the fresh plant it has been 

 assumed that the solid matter forms ten per cent, of the fresh 



* E. Abderhalden, Zeit. f. physiol. Chem., 1898, vol. 25, p. 65. 

 t G. C. Whipple and D. D. Jackson, Journ. New England Water 

 Works Assn., 1899, vol. 14, p. i. 



613*15 



386-84 



56-78 



315*08 



0-388 

 3*973 



0-095 



4*935 

 I-563 



0-0809 



1-949 



1-901 



