538 THE HISTORY OF BIOLOGY 



also elements incorporated in one and the same vital unit; their independence 

 need not be over-stressed. 



In opposition to these two theories, which belong to the eighties, 

 there appeared somewhat later the granule theory of Altmann. Richard 

 Altmann (1851-1901), professor at Leipzig, devoted his attention chiefly 

 to the fundamental substance in which the above-described network of 

 plasm lies embedded, and with the aid of suitable colouring-matter he found 

 in it a mass of grainlike formations — the Latin gramda — of different kinds 

 in different cells. In these he sees the true substance of the cell; he even finds 

 that the threadlike structures which can be produced- by Flemming's method 

 are composed of similar granular formations. Indeed, many of his observa- 

 tions have been confirmed; in the glandular cells especially, the forthcoming 

 secretion first appears in the form of homogeneous granules, which gradu- 

 ally increase in size and assume the form of drops. In most other cells, too, 

 such granular structures appear as expressions of the cell's change of sub- 

 stance; as in nerve- and muscle-cells, of which we shall have more to say 

 later. Altmann, however, sees far more than this in these granule formations; 

 he calls them bioblasts and considers them to be the true elementary organ- 

 isms of which cells and tissues are composed, just as bacterial colonies are 

 composed of various bacteria. He even believes these protoplasmic granules 

 to be of equal value to micro-organisms and would make this his contri- 

 bution towards the solution of the riddle of life, a contribution that he 

 further supplements by finding a resemblance between bioblast and crystal; 

 these two are in fact compared, though hypothetically. These fantastic ideas 

 have naturally been given but little support; Altmann is on firmer ground, 

 however, when he emphatically states that the living substance must be 

 solid and not liquid — an assertion that he bases upon his granule theory 

 in opposition to Biitschli's above-mentioned experiments and speculations. 



These granular structures of the cell-substance have, as a matter of fact, 

 been studied by numerous later investigators, who have given them innu- 

 merable names: "mitochondria," "chondriosomes," etc. They are brought 

 to light by the use of special colouring-methods, but in favourable circum- 

 stances they may also be visible in the living subject, which justifies the 

 assumption that they are not pure artificial products. The same, indeed, is 

 true of the other two plasmic structures: the fibre and the froth structures. 

 M. Heidenhain rightly points out the possibility of all three structural forms' 

 existing in one and the same cell. But this would also go to show that none 

 of the structural theories is capable of forming the basis for a uniform con- 

 ception of what living matter is really composed of. Heidenhain therefore 

 holds that the common structure of the living plasm must be sought beyond 

 what is microscopically visible — that it consists in a system of minute 

 particles that possess the qualities of life, principally that of multiplication 



