Charels Nessler
Chapter XII – Measuring Our Hair Production
Chapter XII of The Story of Hair marks a noticeable shift in Charles Nessler’s work.
After extensive theoretical arguments in earlier chapters, Nessler now turns toward a more practical and technical question:
👉 how can hair growth be measured accurately?
This chapter introduces methods, tools, and calculations intended to transform hair from a subject of speculation into something that can be quantified and compared.
Hair Growth as a Measurable Process
Nessler begins with a general observation:
human hair grows on average about half an inch per month
He acknowledges:
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individual variation exists
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coarse hair grows faster than fine hair
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scalp conditions can differ
👉 Important shift:
Hair is no longer just symbolic—it becomes a measurable biological output.
Establishing Growth Rate
To measure hair production, Nessler proposes a practical method:
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select small areas of the scalp
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shave, bleach, or mark them
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allow new hair to grow
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measure the regrowth over time
👉 Key idea:
Hair closest to the scalp represents new production and can be used as a reliable indicator.
Measuring Scalp Area
A major part of the chapter focuses on determining total scalp surface.
Nessler introduces:
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geometric diagrams of the head
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division into measurable sections
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standardized measurement lines
👉 Example from the diagrams:
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ear-to-ear measurement
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crown line
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neck width
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forehead width
These measurements are then combined to calculate total scalp area.
Original Method (Diagram-Based Measurement)
Nessler suggests:
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dividing the scalp into geometric shapes
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calculating areas using triangles and rectangles
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combining them into total square inches
He notes:
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adult scalp area varies roughly between 95 and 140 square inches
👉 This is one of the most technical sections of the entire book.
Hair Density and Distribution
Next, he addresses density:
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number of hairs per square inch
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variation across the scalp
He observes:
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hair is denser near the crown
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less dense near edges
👉 Important:
Density must be measured separately from growth rate
From Length to Volume
Nessler moves from simple growth to total production.
He combines:
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hair length
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density
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scalp area
to calculate:
👉 total yearly hair production
Example (from his calculation):
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average growth → 6 inches per year
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combined with density → measurable volume
Weight as the Key Measurement
One of his most important conclusions:
👉 weight is the most accurate way to measure hair
“This calculation of hair produce by weight is the only truly accurate method.”
He explains:
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hair bundles can be weighed under pressure
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density and volume translate into grams
Example:
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approx. 11 grams per cubic inch of hair
Special Measurement Tools
Nessler even introduces specific instruments:
Tool “A”
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adjustable square frame
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isolates a defined scalp area
Tool “B”
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measuring slit device
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records hair length precisely
👉 These tools allow:
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consistent measurement
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repeatable results
Difficult Cases
Nessler also addresses complications:
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thinning hair
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bald areas
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uneven density
In such cases:
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hair must be shaved and regrown
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measurements taken over time
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additional body areas (arms, chest) may be included
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Purpose of Measurement
The goal of this system:
👉 create a scientific basis for comparison
He argues:
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without measurement → no real knowledge
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observation alone is unreliable
“How can one judge of loss or gain without a scientific basis of comparison?”
Conclusion of Chapter XII
Chapter XII represents one of the most practical sections of the book.
Nessler’s key ideas:
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hair growth can be measured systematically
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scalp area, density, and length must be combined
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weight provides the most accurate result
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scientific measurement is essential for understanding hair
This chapter attempts to move hair research from theory into quantifiable science.
Modern Scientific Perspective
Modern science confirms part of Nessler’s approach—but with important refinements.
✔️ What is valid:
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hair growth can be measured ✔
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density varies across the scalp ✔
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scientific measurement is essential ✔
❌ What is outdated:
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simplified geometric scalp models ❌
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weight as primary measurement ❌
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lack of microscopic analysis ❌
Modern methods include:
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phototrichograms
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digital scalp imaging
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follicle density analysis
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growth cycle tracking
Today, hair measurement is:
👉 precise, standardized, and technology-driven
What remains important
Nessler’s key contribution here:
👉 he insists on measurement over speculation
This marks a turning point:
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from theory → to method
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from observation → to data
OPTIONAL SECTION
→ Chapter 13
→ Chapter 11
→ Back to Overview
→ The Permanent Wave – Invention, Method and Impact
Below you find the original scanned version of Chapter XII from The Story of Hair by Charles Nessler.