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KANSAS UNIVERSITY SCIENCE BULLETIN. 



gartner ('04) has stated. But there is not sufficient difference 

 either in form or size to substantiate a theory of persistence of 

 this individuality. 



In studying the size of the chromosomes more carefully I made 

 sketches of from five to eighteen chromosomes in each of fifty cells 

 in the Neuroplasm, 21 cells in the ectoplasm, 15 cells in the muscle, 

 15 cells in the connective and 10 cells in the pigment. I did this 

 for each of the three different ages of the Ambystoma, using the 

 camera lucida and micrometer, as described previously. The 

 accompanying table gives a record of the results obtained. For 

 convenience we will use the series number of the slide 628 to 

 represent the youngest and 630 the oldest. 



No. of slide. No. cells. 



Tissue. 



Av. Width. Metaphase. Anaphase. Extremes. 



Great care was taken to use only chromosomes in which the 

 complex lay perpendicular to the line of sight lest there be a 

 possibility of foreshortening. In many cases it was possible to 

 find a complex, or nearly a complete complex, in which the 

 diameter was uniform, and in which the length seemed to form 

 some kind of a mathematical series if not an arithmetical one. 

 But this was the exception rather than the rule. We know that 

 the larger the number entering into an average, the less is the 

 liability of error, and the more general and reliable becomes our 

 deduction. For this reason I tested 50 nerve cells instead of one 

 or two. I measured the diameter of from 5 to 18 chromosomes, 

 in each of these cells and worked out the average for each cell 

 and then the average for the entire 50 nerve cells. We find by 

 referring to the table here for No. 628 that the average width is 

 .87 ,". The average for the metaphase and anaphase alone are 

 .85 ," and .77 ," respectively. But in the individual cells there is a 

 greater difference. The averages for the cells range from .65 to 



