178 
CHARLES L. PARMENTER 
sketching it. The chromosomes were then numbered consecu¬ 
tively, the number being placed on both ends of each chromo¬ 
some. This method avoided any possibility of overlooking any 
chromosome or of counting any chromosome twice. 
2. Clearness and classification of the complexes. All the com¬ 
plexes counted were polar views of late prophases and of meta¬ 
phases and have been divided into three classes on the basis of 
their clearness. The first class consists of forty-five complexes 
in which every chromosome was so clearly separated from adja¬ 
cent chromosomes that it could be optically traced continuously 
over its entire length, without losing sight of it at any point. 
Only the counts from complexes of this group are submitted 
as data which are unquestionably free from objection and 
uncertainty. 
In the second class of cells there are eighteen complexes in 
which the chromosomes are all exactly as clear as those of the 
first class, with the exception that either one or two chromosomes 
cannot be clearly traced over their entire length as they could 
be in class I and therefore might possibly be hypercritically 
considered to necessitate interpretation. 
The three cells of the third class differ from those of the 
second class in that they each contain places in which the number 
of chromosomes cannot be determined with confidence and 
consequently are actually subjects for interpretation. 
Complexes of the first class. Complexes of this class are 
represented by figures 1 to 8 which have been made in carbon 
and are attempts to represent the actual appearance of the 
chromosomes and their relative positions in the complexes. Rep¬ 
resentative cells from each of the tissues studied, except the 
mesentery and lung, have been so drawn. Other complexes of 
this group have been outlined in ink, figures 9 to 20, to give a 
further assurance of the nature of the complexes constituting 
this class of conditions. 
Since it is impossible to represent chromosomes in a drawing 
as clearly as they are seen in a cell, it is necessary to consider 
briefly this situation in order to prevent misunderstanding, and 
incorrect impressions concerning the clearness of the cells and 
