442 BIOLOGY AND ITS MAKERS 
stature, the law of ancestral inheritance, the statistical study 
of variations in spines, markings on shells, etc., etc. (Galton, 
Pearson, Davenport). 
Other branches of biology that have been greatly devel- 
oped by the experimental method are those of bacteriology 
and physiological chemistry. The advances in the latter 
have greatly widened the horizon of our view regarding the 
nature of vital activities, and they compose one of the leading 
features of current biological investigation. 
Some Tendencies in Anatomical Studies. Cell-Lineage.— 
While experimental work occupies the center of the stage, 
at the same time great improvements in morphological 
studies are evident. It will be only possible, however, to 
indicate in a general way the direction in which investigations 
are moving. We note, first, as in a previous paragraph, that 
the improvement in morphology is generic as well as specific. 
Anatomical analysis is being carried to its limits in a number 
of directions. The investigations that are connected with 
the study of cells afford a conspicuous illustration of this 
fact. Studies in cell-lineage have led to an exact determina- 
tion of cell-succession in the development of certain animals, 
and such studies are still in progtess. Great progress also 
has been made in the study of physical structure of living 
matter. The tracing of cell-lineage is a feat of remarkably 
accurate and patient work. But, however much this may 
command our admiration, it has been surpassed (as related 
in Chapter XI) by investigations regarding the organization 
of the egg and the analysis of chromosomes. Boveri, Conk- 
lin, Wilson, and others have shown that there are recognizable 
areas within the protoplasm of the egg that have a definite 
historical relationship to certain structures in process of 
development. This is the basis upon which rests the doctrine 
of pre-localization of tissue-forming substances within the 
protoplasm of the egg. 
