CHAIN OF CYCLOSALPA AFFINIS 437 
ing and decreasing; that they have phases; that the time element 
being considered, they change in value from moment to moment. 
How then can we treat any particular phase, or stage of such phe- 
nomena so as to meet the demands of rigorous science without 
considering each phase in relation to the other phases? So far 
as they are treated without such reference the procedure would 
seem to be of the nature of ‘random observations’—of the ‘grab- 
sample’ kind—that always, whether in common life, business, or 
science finally proves to be inadequate if not disastrous. Astron- 
omy, physics, chemistry, and in general geology, have passed quite 
out of this portion of their careers. 
Taking it as established that biology is allied in essential nature 
with these older, less complex sciences, does it not seem inevit- 
able that it too must move on and leave its cruder, haphazard 
methods behind? Does it not look as though this very fact of 
periodicity, this gradual come-and-go of things in the operations 
of organisms is to be one of the chief if not the chief way out? 
To press the inquiry a little closer, does it not look as though the 
wide prevalence of repetitive parts in reproduction and growth, 
which though like one another still differ from one another by 
some regular quantity, is to be one of the most important, though 
only one, of these exits? 
It appears to us that cell division, for example, including the 
division of all cell parts subject to this process will have to be 
looked at sooner or later from this standpoint. Take the Fora- 
minifera, for instance, unicellular organisms (according to the 
current interpretation) the bodies of great numbers of which be- 
come divided into many sections called nodes and chambers. 
In the great majority of species, as a glance at figures enables one 
to see, these divisions fall into quantitatively differentiated series. 
To make the point more cogent we introduce figures of two species 
Reophax membranaceus Brady (fig. 21) and Peneroplis arietinus, 
Batsch. sp. (fig. 20). Now let one compare these organisms with 
the salpa chain, the one, for example, represented in fig. 18, and 
catechise himself something like this: surely there is some resem- 
blance between these objects. Both are composed of a considerable 
number of sections rather regular in form and much like one an- 
