10 ELEVENTH REPORT. 



the description would be considered faulty. It does not require much time 

 or many generations to induce structural changes in cells; even reaching 

 some of the more intimate and essential organs involved. The anthrax 

 micro-organisms become sporeless ; the tubercle bacillus may perhaps furnish 

 branched forms; the pleomorphic appearances of the acetic bacteria are well 

 known; the hay bacillus may be lengthened or shortened, all through the 

 influence of the nutrients furnished. Some of these changes appear to be 

 more or less permanent and the exact limits of the changes cannot be placed. 

 It is ciuite a common feeling that micro-organisms may be easily led into one 

 channel or the other, but to what extent is still an unknown factor. The 

 subjects of variation and mutation are no less common or striking with 

 micro-organisms than with the species higher in the order of life forms. 



Besides the influence of nutrition, which seems to have a marked effect 

 upon the structure, other factors, as the air, temperature, light are equally 

 prominent in shaping the form of a single celled organism. Owing to this 

 fact, it is not so far removed from actual evidence to state that the structural 

 or morphological features find their directive in the molecular complex of 

 the living form. Again I quote from Wilson: "When we consider the 

 analogy between the centrosome and the l)asi-chromatin granules, when we 

 recall the evidence that the latter graduates into the oxy-chromatin granules, 

 and these, in turn, into the cA'to-microsomes, we must admit that Briicke's 

 cautious suggestion that the whole cell might be a congeries of cell propoga- 

 ting units of a lower order is today not entirely without support of facts." 

 It would seem that slow, yet persistently jirogressive variation is quite 

 within the power of cell life, and that catach'sms of different degrees may 

 give rise to variations and mutations of corresponding extent. 



Studying the micro-organism in the light of the structure of other cells, it 

 is found that there exists a great similarity. The chromatin granules which 

 may or may not be regarded as indejDendent parts, are found distributed 

 through the protoplasm of most micro-organisms. These may be identical 

 with the chromatin which l^elongs in the formation of the spireme. Swellen- 

 grebel points out a spiral in Bacillus maximus buccalis extending along the 

 long axis of the cell. It is found in 3'oung and adult cells. This filament 

 possesses an active affinity for nuclear colors, and in composition is closely 

 allied to chromatin. The chromatic portions of this filament corresponds 

 to linin. From this structure appears to arise a chromosome which, eventu- 

 ally, divides into two daughter chromosomes, each in turn entering into 

 the formation of a daughter cell. This work of Swellengrebel brings one to 

 the belief that there exists karyokinesis in the bacterial cell. Mencl has 

 claimed this mitotic division in the case of Bacillus of periplaneta orientalis. 

 Schaudann l^elieved that he was able to demonstrate the rudiments of sexu- 

 ality in bacillus biitschlii and would distinguish it from the ordinary vegeta- 

 tive division. This same author has studied in detail the different stages of 

 development in the flagellates, notabl}", trypanosoma, and has endeavored 

 to demonstrate a close relation with the stages of development in the spiro- 

 chaete. In this, Novy does not agree, and indicates clearly that there may 

 exi.st some confusion in the description of species considered. For our 

 purpose, it is plainly evident that there is sufficient evidence an the one hand, 

 and sufficient ignorance on the other, to make it plausible that there is a 

 general method of cell division running through the world of micro-organisms, 

 modified in one way and another in the individual species, which is, very 

 similar to that found in all living cells. 



If environmental conditions, such as nutrition, light, heat, temperature, 



