30 H^EMATOCOCCUS LESS. 



ably belonging to the class of amides, one of the best 

 known of which asparagin has the formula C 4 H 8 N 2 O 3 . 

 Then further combinations take place, substances of greater 

 and greater complexity are produced, sulphur from the ab- 

 sorbed sulphates enters into combination, and proteids are 

 formed. From these, finally, fresh living protoplasm arises. 



From the foregoing account, which only aims at giving 

 the very briefest outline of a subject as yet imperfectly un- 

 derstood, it will be seen that, as in Amoeba, the final result 

 of the nutritive process is the manufacture of protoplasm, 

 and that this result is attained by the formation of various 

 substances of increasing complexity or anastates (see p. 18). 

 But it must be noted that the steps in this process of con- 

 structive metabolism are widely different in the two cases. 

 In Amoeba we start with living protoplasm that of the prey 

 which is killed and broken up into diffusible proteids, 

 these being afterwards re-combined to form new molecules 

 of the living protoplasm of Amoeba. So that the food of 

 Amoeba is, to begin with, as complex as itself, and is first 

 broken down by digestion into simpler compounds, these 

 being afterwards re-combined into more complex ones. In 

 Hsematococcus, on the other hand, we start with extremely 

 simple compounds, such as carbon dioxide, water, nitrates, 

 sulphates, &c. Nothing which can be properly called diges- 

 tion, i.e., a breaking up and dissolving of the food, takes 

 place, but its various constituents are combined into sub- 

 stances of gradually increasing complexity, protoplasm, as 

 before, being the final result. 



To express the matter in another way : Amoeba can only 

 make protoplasm out of proteids already formed by some 

 other organism : Haematococcus can form it out of simple 

 liquid and gaseous inorganic materials. 



Speaking generally, it may be said that these two methods 



