30 FUNDAMENTAL PKOPERTIES 



Braun, that nothing like a nucleus was to be found in many Algae. 

 Thus the latter says {loc. cit. p. 174) " in particular famiUes of the 

 Algae, as, for example, in the Palmellaceas, Chlorococcaceae, Oscilla- 

 torieas, and Nostochinese, as also in the large-celled Cladophorae, 

 and the unicellular Algae with unlimited growth of the cell 

 (Vaucheria, Codium, Caulerpa), no trace of a nucleus has yet been 

 discovered." Yet in these latter so-called (but wrongly so-called) 

 ' unicellular ' Algae, and in the others just mentioned, all the 

 fundamental properties of living things — even in some of them 

 (as in Vaucheria) the formation of active ciliated reproductive units 

 — are manifested, notwithstanding the absence of a nucleus. It 

 is useless, therefore, as was formerly the case and as happens only 

 too frequently now, to attribute all the important phenomena 

 occurring within a cell to the effects of its influence. Still, 

 though it is clear that no such structure is necessary to enable 

 a unit of protoplasm to exist as an independent vital unit, it has 

 been found, as we shall see later on, that where present it exercises 

 a most important influence in the production of one of the 

 fundamental phenomena of living matter — namely, the act of 

 assimilation, whereby its own proper structure is built up by a 

 living unit during its process of 'growth.' 



We are now in a position to speak briefly concerning the various 

 fundamental properties of elementary living units ; and what we 

 shall have to say will not concern cytodes only, but wiU be appUc- 

 able also to 'unicellular organisms,' and will go to show how 

 closely, in each case, their vital manifestations are related to, and 

 correlated with, ordinary physico-chemical processes. 



This subject has been very ably and logically treated in a little 

 book by F. le Dantec, entitled " La Matiere Vivante," ' to which 

 several references will be made. 



(i) One of the first and most striking characteristics of the 

 lowest forms of life, as viewed under the microscope, is the power 

 possessed by many of them — though others do not possess it — of 

 what is apparently spontaneous or instinctive Movement. And it is 

 precisely this appearance of spontaneous movement which has 

 tended to foster the notion that even in such elementary units their 

 movements are due to an "internal vital principle." But, as a 

 matter of fact, these movements, like other elementary manifesta- 



' Paris, 1893. One of the Vols, of the " Encyclopedie Scientifique des Aide- 

 Memoire." 



