A STUDY OF FUNDAMENTAL BARS IN FEATHERS. I/ 1 



did not appear in the territory occupied by a " fundamental bar." 

 Since these defective lines are laid down at approximately the 

 same time each day as is proved by the regularity in the dis- 

 tances separating them we are forced to the conclusion that 

 the defective lines are normally laid down at night, and that a 

 lowering of the blood-pressure is associated with the production 

 of defective areas, and, therefore of defective lines, for, that the 

 defective line stands for the initial stage of the defective area is 

 as certain as that an area has more dimensions than a line. The 

 evidence in part is, that one sees all possible intergradations, that 

 each marks off a day's growth, that when the area occurs it 

 always falls in the place for the line, that a certain part of the 

 line only may be transformed into the obviously defective area, 

 etc. That there is a reduction of cell-growth and cell-division in 

 the defective area is proved absolutely by an examination of the 

 adult morphology of an exaggerated defect, as it is also by the 

 histology of the defects in the feather-germ. 



That the low blood-pressure occurs at night is evidenced by 

 the experiment of the chick in the amyl nitrite. That it occurs 

 between midnight and six in the morning may be inferred from 

 the fact that the lowest daily temperature in birds falls between 

 these hours. Reasoning from the facts known in mammals we 

 may assume that the minimum blood-pressure coincides in point 

 of time with the minimum temperature. I have not been able to 

 get the daily blood-pressure curve of birds, owing to the diffi- 

 culty of doing so in birds of small size. The ostriches might 

 well be used for that purpose. At this point I may suggest that 

 the ostriches will doubtless cease to interpolate defective areas in 

 their plumes as soon as they can find the perfect diet, and the 

 various life conditions which will give them well-nourished bodies 

 and strong, effective circulations. After all, these two are one. 



THE RELATION OF NUTRITION TO THE DEFECTS. 

 At the very beginning of this study, it was thought that the 

 defective areas stood in a certain relation to a faulty nutrition. A 

 number of experiments were made to determine this. A number 

 of young ring doves were alternately starved and fed, with the 

 result that in these birds the defective areas appeared in the 



