1887.] NEW-YORK MICROSCOPICAL SOCIETY. 49 



condition, enabling the animal, so protected, to resist moisture 

 by reason of the grease (or whatever it is) having a disinclina- 

 tion to permit moisture to remain upon the fur of the animal. 



Now the first question to be solved by some observers is this. 

 How do fur fibres grow ? It is ridiculous to think that they 

 are projected from the skin of the animal point first in a com- 

 pleted condition. 



This view appears to be answered by the scales themselves, 

 which would prevent any such growth. If this is not so, how 

 do the pigment cells find their way through the ductless portion 

 adjacent to the skin, or butt end of the fibre, to the points be- 

 tween the air cells ? In fact the question ^presented is, how 

 does a fur fibre grow ? The writer has never been able to solve 

 this problem. Some worker with the microscope is invited to 

 take up this question and find its solution. 



The next question to be answered is this. Do the scales 

 themselves by their union at their butts, or inner ends, form the 

 wall of the fibre ; or do the scales grow out from a separate and 

 distinct wall of substance, forming a tube as it were around the 

 air and pigment cells, and inside of the roots or inner ends of 

 the outer scales ? The writer has never been able to solve this 

 problem. 



It cannot be doubted that the pigment cells find their way to 

 the exterior of the fibre, emerging from under the scales. The 

 question here presented is : How, or through what channels do 

 they find their way, from the interior to the exterior of the fibre ? 



While referring to the pigment cells this question is presented: 

 Are the pigment cells massed in a solid disc across the central 

 tube of the fibre ; or are they merely a lining, surrounding an 

 opening through the fibre ? Do they oppose themselves as a 

 barrier to the passage of other pigment cells ; or do they merely 

 form a ring, at approximately equi-distant portions of the fibre's 

 length ? The great difficulty of cutting sections in any direction 

 of a fur fibre has prevented further light on these interesting 

 points from being obtained. 



Somewhat imperfect sections have been made, and they go to 

 show that each fibre is oval ; and it would appear that a clear 

 passage existed through the mass of pigment cells, but such ob- 

 servations have been altogether too uncertain to allow of any 

 definite answer being given to the questions here asked. 



