THE FUNDAMENTAL ORGANIZATION 73 



they diminish perceptibly in size and increase in size when the 

 chromatin content becomes stationary. From these results, con- 

 firmed by van Herwerden (1917) on yeast cells, Reichenow con- 

 cluded that volutin grains play a most important part in the vital 

 activities of the cell and he regarded them as a reserve store of 

 nucleo-proteins for the purpose of chromatin growth in the nucleus. 

 They appear to be formed in the cytoplasm and, if these observa- 

 tions are well founded, are entirely different in origin and in function 

 from the other minute granules which they closely resemble. The 

 importance of these conclusions in problems connected with biology 

 of the cell warrants the demand for further and more complete 

 observations and experiments. 



3. Mitochondria. — The chondriome of a cell consists of the aggre- 

 gate of cytoplasmic substances of lipoidal nature appearing in the 

 form of minute granules termed mitochondria, as strings of granules 

 termed chondriomites, or as smooth filaments termed chondrioconts 

 according to the terminology of Benda (1903) and Meves (1907). 



The lipoidal make-up is shared with the Golgi apparatus, another 

 group of cytoplasmic substances which are equally well distributed 

 and similar in form and in reactions to mitochondria, but which 

 are regarded as distinct from the chondriome and with different 

 functions in the cell. 



Some of the lipoidal substances making up the chondriome are 

 evidently autonomous bodies in the cell, while others, more transi- 

 tory in nature, probably result from metabolic activities. It is 

 quite probable, as Alexeieff suggests (1928), that different states or 

 stages of a common type of substance are represented in different 

 organisms and the terms mitochondria chondriomite, chondriocont, 

 etc., have merely a morphological significance. Of these the mito- 

 chondria appear to be the original neutral and most widely dis- 

 tributed of the lipoidal substances, and as such they belong to the 

 fundamental organization. 



Mitochondria are minute inclusions in the cytoplasm, varying 

 in size from 0.5 ju to 1.5 ju. They may be spherical granules or 

 rod-shaped, resembling bacteria, or crescentic or sickle form. 

 (Fig. 37.) They have been identified in so many different types 

 of Protozoa that their universal distribution may be assumed with 

 assurance. 



Except in a very general way the chemical make-up of mitochon- 

 dria is unknown. They become reduced in size or disappear after 

 treatment with alcohol or acetic acid, but there are wide differences 

 in the times required to bring this about. They blacken with 

 osmic acid, turn blue green with Janus green B, or red with Janus 

 red (Horning, 1926). Faure-Fremiet (1910) who was the first to 

 recognize mitochondria in Protozoa regarded them as a combination 

 of albumin and phosphates of fatty acids. Today there is no 



