198 REINHARDT THIESSEN 



The humic matter, or cellulosic degradation products. — In the 

 photographs just referred to, particularly noticeable at ^-i (Fig. 19), 

 there will be recognized besides the strips designated as anthraxylon 

 constituents, other strips similar in appearance but thinner and 

 more irregular in width and bearing no marks of plant structure. 

 Besides these, there are other more globular constituents, some of 

 very small sizes, others very finely divided. These are of the same 

 general appearance and color as the anthraxylon matter and 

 constitute part of the attritus. Most of this matter evidently is 

 of the same general origin as the anthraxylon components, and 

 may be collected into one class and designated under the general 

 term of "humic" matter. Under "humic" matter then is con- 

 sidered the cellulosic degradation products in a state of division 

 finer than the smaller anthraxylon components but not including 

 resinous, cuticular, spore, or carbonaceous matters. There is 

 no hard-and-fast line of distinction between the smaller anthraxylon 

 components and the humic matter. The particles constituting the 

 humic matter in general no longer bear visible marks of plant or 

 cell structures and are smaller in sizes. 



It should be emphasized that the humic matter consists very 

 largely of definitely definable particles and not of a vague plastic 

 or homogenous mass, and only a comparatively small proportion 

 is so finely divided as to lose its individuality even under very 

 high magnifications. When this stage is reached, we enter the 

 realm of colloidal conditions, and proper methods will here also 

 show that the matter consists of individual particles. 



There must be included in the term humic matter, substances 

 of a wider origin than the anthraxylon, such as gums, pectins, cork, 

 bark, and other substances closely allied to the cellulosic materials. 

 In analagous studies of peat, where the constituents are more easily 

 identified, there is very little matter that is of other origin than 

 cellulosic; and if the formation of coal and peat is to be considered 

 analogous, the conclusion must be drawn that but a small propor- 

 tion of the humic matter in coal can be other than of cellulosic 

 origin. This, however, does not dispose of a long list of substances 

 known to exist in plants, such as tannins, alkaloids, oils, terpenes, 

 camphors, etc.; but if these or their derivatives are still present 



