1877 Schulin

 
Beiträge zur Histologie der Haare. Zeitschrift f Anatomic Entwick Bd II. Leipzig: von F.C.W. Vogel, 1877:375-410 (Fig. 2).

View Figure  		Fig. 2  [Fig. 4] Anlage of a hair from the temporal scalp of a 18-cm-long human fetus. 1/150. b = the developing papilla; c. = anlage of the sebaceous gland; d = secondary anlage of a hair; e. = protuberance corresponding to the insertion of the m. arrector pili (Unna"s bulge); f. = m. arrector pili. (Reproduced with permission.)
 

Message

 
"The bulge" plays no role in the follicular cycle, contrary to the opinion of Unna.
 
"The bulge" is simply the site for insertion of the muscle of hair erection, and it becomes protuberant as a consequence of the tug of a muscle upon it.
 

Critique

 
Schulin denies the hypothesis that "the bulge" is requisite for the follicular cycle.
 
Schulin did not realize that "the bulge" encircled a follicle; his drawings depict it as being unilateral. This misperception prompted his erroneous conclusion that "the bulge" came into being consequent to the pull of a muscle on the outer sheath.