64 GENERAL PHYSIOLOGY 



lamellar particles in the yolk of eggs; and even the small oil- 

 droplets and fat-globules that occur in various tissue-cells, 

 especially in the liver and the cells of subcutaneous connective 

 tissue. Moreover, particles of ingested food, transformed food- 

 constituents, undigested food-stuffs, and products of cellular 

 metabolism, i.e., substances that are playing or have played the 

 most various rdles in cell life, are put into the same category, and 

 are considered as elementary organisms. In the second place, 

 Altmann does not prove for one of all these forms that they show 

 general vital phenomena, nor would success in such an attempt be 

 expected, especially in the case of an oil-droplet or a pigment- 

 grain lying within the cell. Nevertheless, such proof must be 

 furnished if the term " elementary organism " is to be allowed. 

 Regarding Altmann's belief that bacteria must be considered 

 as free-living granules, not only is there no evidence for this 

 view, but lately the striking investigations of Biitschli ('90) 

 have afforded proof that bacteria are complete cells, and hence 

 organisms that Altmann considers colonies of bioblasts. 



These considerations suffice to overthrow Altmann's idea. And, 

 in general, it seems entirely inadmissible to regard as elementar}- 

 organisms structures that have no analogies with free-living 

 organisms. If this be allowed, the conception of the organic 

 individual collapses, for it is then not justifiable to consider any 

 one portion of the living substance more than another as consti- 

 tuting the elementary organism. The term can be applied with 

 equal justice to an atom of oxygen or carbon, or any other atom- 

 that takes a direct part in the life-process. There would be as 

 many elementary organisms as organic elements. How to define 

 an organism or an organic individual is one question, what in 

 general to call living is another. The latter will be discussed later. 

 As to the former, if the conception of the organic individual is not 

 to be given up, it must be regarded as an unconditional requirement, 

 that the organism be characterised by the presence of all those vital 

 phenomena that have to do with self-preservation. Only the cell 

 fulfils this condition ; it is, therefore, the individual of the lowest- 

 order and the elementary organism. 



2. General and Special Cell- constituents 



The thought that the enormous number of phenomena 

 constituting life are associated in all their essentials with the 

 microscopic bit of living substance that constitutes the living cell 

 is an irresistible stimulus to research. Hence, from the time 

 when the significance of cells as elementary organisms became 

 first recognised until now, a host of investigators have busied 

 themselves with the detailed study of the cell and its con- 

 stituents. Thanks to this, our knowledge of cell-morphology has 



