Chapter XVII – Straight or Naturally Curling Hair
 

Chapter XVII of The Story of Hair focuses on a fundamental question:

👉 why is hair straight, wavy, or curly?

Charles Nessler explores this topic by combining:

• structural explanations

• environmental influences

• and observational comparisons

This chapter marks a shift toward a more physical and environmental interpretation of hair behavior.
 

Natural Curling vs Straight Hair

Nessler begins with an important claim:

👉 so-called “naturally curly hair” is not always an inherent or fixed trait

He questions the idea that:

• hair types can be strictly divided

• straight and curly hair are fundamentally different

Instead, he suggests:

👉 variation exists on a spectrum

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Original Observation (1928)

From the chapter:

• individuals often describe their hair inconsistently

• hair may appear straight at one time and wavy at another

• environmental conditions influence appearance
   

Hair Structure and Shape

Nessler addresses a common belief:

• straight hair → round cross-section

• curly hair → flattened cross-section

He challenges this simplification:

👉 according to him, naturally straight and wavy hair do not differ significantly in structure

However:

• very tightly curled hair (e.g. “kinky hair”) shows structural variation

👉 Key idea:

Most hair differences are less absolute than commonly assumed
 

Hair Growth Pattern

Nessler argues:

👉 all hair grows straight from the scalp

Curling occurs later through:

• external influences

• physical conditions

• environmental interaction

This contradicts the idea that curl is purely determined at the root.
 

Development of Hair in Children

A key observation:

👉 hair type is not immediately fixed at birth

He describes:

• babies with straight hair that later curls

• delayed development of waves

• gradual changes over time

Example:

• hair may remain straight for months

• later begins to curl naturally
   

Hair as Indicator of Health

Nessler introduces an interesting idea:

👉 hair behavior may reflect physical condition

Example from the text:

• a child’s hair failing to curl

• later linked to illness

👉 Suggestion:

Changes in hair pattern may indicate internal imbalance.
 

The Role of Humidity

This is the most important part of the chapter.

👉 humidity is the primary curling factor

Nessler explains:

• hair absorbs moisture from the air

• moisture enters the hair structure

• causes expansion and contraction

Result:

👉 hair begins to curl or wave

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Mechanism of Curl Formation

Process described:

1. hair absorbs moisture

2. internal structure swells

3. expansion is uneven

4. hair bends → curl forms

curling occurs along the line of least resistance
 

Climate Influence

Nessler observes:

• dry climates → straighter hair

• humid climates → increased curling

Examples mentioned:

• mountains

• deserts

• tropical regions

👉 Hair adapts to environment
 

Analogy from Nature

Nessler compares hair to:

• plant tendrils

• branches

• natural fibres

He explains:

• moisture causes curling in nature

• similar mechanism applies to hair

Example:

• plant fibres curling in humidity

• straightening in dry conditions
   

Material Analogy (Clothes Line)

One of his clearest examples:

👉 a clothesline reacts to moisture

• dry → straight

• wet → stretches, twists

Hair behaves similarly:

👉 it responds dynamically to environmental conditions
 

Porosity as Key Factor

Nessler introduces:

👉 porosity determines curling ability

He explains:

• porous hair absorbs more moisture

• more absorption → more curling

Thus:

• thick hair → stronger curl response

• fine hair → weaker response
   

Conclusion of Chapter XVII

Key ideas:

• hair types exist on a spectrum

• curling is influenced by environment

• humidity is the main factor

• porosity determines response

• hair behavior is dynamic
   

Modern Scientific Perspective

Modern science partially supports these observations.

✔️ What is correct:

• humidity affects hair ✔

• moisture changes hair shape ✔

• porosity influences behavior ✔

❌ What is outdated:

• curl is not primarily environmental ❌

• hair shape is largely genetically determined ❌

Modern explanation

Hair shape is determined by:

• follicle shape (round vs oval)

• keratin structure

• genetic factors

Humidity:

• enhances or modifies curl

• but does not create it fundamentally
   

What remains relevant

Nessler’s strongest insight:

👉 hair is dynamic and reacts to environment

This is still true today:

• humidity changes curl pattern

• hair responds to climate

• styling depends on moisture
   

Final Interpretation

Chapter XVII shows Nessler at his most observational.

He combines:

• physics

• environment

• everyday examples

Hair becomes:

👉 a material that reacts to the world around it
 

OPTIONAL SECTION

→ Chapter 18 (next)
→ Chapter 16

→ Back to Overview

→ The Permanent Wave – Invention, Method and Impact

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Below you find the original scanned version of Chapter XVII from The Story of Hair by Charles Nessler.

Download Chapter XVII (Original Scan, 1928)