By Dr. Gary Noel Ross

COTTON. SUGARCANE. RICE. TOBACCO.
All, of course, are major crops that have played colorful roles throughout Louisiana's unique history. But the list is incomplete, lacking the most colorful crop of all: indigo.

Click here for full size photo.

For the early l8th-century Spanish and French colonial settlers in the subtropical lands of the Mississippi delta, indigo (café sauvage) was the very lifeblood of the land. It can be argued that indigo, as the fledgling colony's first commercial crop, helped Louisiana prove itself as a powerful economic and political power not to be spurned.

But just what is indigo? In common usage, the word refers originally to a blue dye obtained from a leguminous (pea family) plant of the same name.

Considered the oldest and most durable of dyes, indigo is often labeled the "King of Dyestuffs." Its method of production can be found in ancient Indian Sanskrit. Many mummies from Egyptian and Incan tombs are wrapped in indigo-dyed cloth, and the earliest Persian rug dated from the 5th century B.C. contains authenticated hues from indigo.

In powdered or paste form, indigo has been used as a paint, a cosmetic (eye shadow), and an astringent for cleaning wounds and ulcers. So highly prized was the dye that its true nature was a carefully guarded secret for thousands of years. Even as late as 1705, some dyers believed indigo to be a mined mineral.

Click here for full size photo.

In 1763, Louisiana's number one export was indigo, with a value of over $1.2 million. By 1800, however, production was down drastically. Some historians attribute this to exceptionally wet growing seasons and attacks by uncontrollable insects.

Other chroniclers of the time reported that indigo developed a bad reputation because it produced a rust on neighboring wheat crops and because the method of dye production killed most of the laborers.

Click here for full size photo.

Plantation production ceased about 1806, although limited plantings to satisfy personal use continued for some time afterward. The dye eventually received a decisive blow in 1878 when a laboratory-concocted chemical alternative was prepared in Europe.

Although it was widely agreed that the synthetic was not as intense or as durable as the real indigo, the laboratory version was cheaper and required less time to manufacture. And so, throughout the Louisiana delta, the King of Dyestuffs was dethroned and replaced by a new monarch, King Cotton.

Today, synthetic indigo still retains a revered position among textile manufacturers worldwide. With an annual production of 14,000 tons, synthetic indigo is the major industrial dye. Levi Strauss & Company, for example, annually markets over one billion pairs of blue jeans, a universally fashionable denim produced in an indigo dye bath.

But in Louisiana's southwest Cameron Parish, the past is not dead history: indigo thrives! To be sure, the great plantations of yesteryear exist no more. However, in 1991, I by chance discovered Indigofera suffruticosa growing commonly there in the sandy soils of the cheniers, the narrow, oakcovered ridges of dry land that rise above the surrounding marshes.

"Thus, indigo's infamous legacy seems to be true. The King of Dyestuffs was a malevolent ruler whose reign was tainted with death."

The plants are particularly abundant along pasture fences bordering the north side of many of the roads between Grand Chenier and Cameron. These plants are easy to recognize: perennial shrubs sprouting in late spring from persistent root stocks; multiple stalks up to six feet in height; green, feathery leaves that shimmer with even the gentlest of breezes; delicate, pea-shaped, pinkish-coppery-colored flowers in late summer followed by green (and later black) bean-like seed pods clustered banana-fashion in October and November.

The indigo plants of Cameron Parish are without doubt relics of a spent era. Curiously, I found no local Cameron Parish residents who could recognize the indigo plants that were growing there in obvious places.

It is true that the French word indigo is part of the local lore. The term, however, refers to other varieties of weedy leguminous plants common in marshes and in rice fields. And although dove hunters throughout most of the rice-growing parishes frequently refer to the small seeds often found within the stomachs of their quarry as "indigo," upon examination the seeds prove to be those of other legumes.

I was disappointed. I had hoped that the Cameron folk could shed some light on the persistent and perplexing myth surrounding indigo's ill effects on animal and human life. In treatises describing indigo production in Louisiana, there are statements claiming that the dye-producing process "killed fish in streams," "repulsed livestock," and was so "disgusting and disagreeable" that it "on average killed every Negro [slave] employed in its culture in the short space of five years."

A reinforcement of these extraordinary claims is found in a historical novel set in El Salvador and written by a prizewinning Latin American author: "For over four centuries the process of fermenting and precipitation ... had been turning the area's inhabitants yellow. Tubercular. Cancerous."

Such strong assertions were especially puzzling to me. In the early 1980's, I had spent considerable time researching indigo production in southern Mexico, the only region in the western hemisphere where the crop is still commercially grown and processed-albeit on a small scale.

There I had learned that the indigo farmers have never associated any illness with their trade. In fact, indigo plants are usually fed to pigs as a food. Furthermore, the verbal history within the culture contains no mention of indigo-induced disease.

The historical snips from Louisiana and El Salvador and the testimony of the Mexican farmers seemed to clash. Could this mystery be solved, especially since the Cameron citizens could offer no assistance?

After lengthy conversations with high-tech chemists and hours of thumbing through chemical texts in university libraries, I think I have at last found a clue. You see, indigo dye production is both physically and chemically complex. To be specific, the process involves a multiple-vat steeping system.

Click here for full size photo.

First, the cut plants are fermented under warm water. Second, the resulting solution is "beat" to introduce oxygen. Third, ashes or mucilage from plants is added to the aerated fluid to induce precipitation, a process that separates sediment from a solution. Fourth, the rich blue sediment is dried, cut into bars-called cakes-and then marketed.

Amazingly enough, this final product is still not the actual dyestuff. As with most dyes, indigo must be dissolved in water before the pigment can impregnate fiber. Unfortunately, indigo cakes are insoluble in water. To remedy this dilemma, yet another processing vat must be engaged.

Although recipes vary, all are based on the premise that alkaline media can chemically alter indigo into a water-soluble form. The list of ingredients that have been used in this "blue vat" includes bran, madder (an herb), iron compounds, potash, lime, soda, and even aged human urine.

After several days of fermenting in the dark, the solution -- now the color of untarnished copper-has been primed. To dye, a fabric is submerged for a few minutes and then raised into the air. As if by magic, the fabric begins assuming the characteristic blue color that from this point on is virtually indestructible.

Although the chemical literature is explicit that no toxic products or byproducts are created during the laboratory production of synthetic indigo, natural indigo is another story. Ostensibly, the natural dyestuff is composed of at least seven similar but distinct complex chemicals. Of these, at least one -- "indigo yellow" -- has proven to be mutagenic, meaning that it tends to increase the frequency or extent of genetic mutation, possibly causing cancer.

Furthermore, it is quite probable that other chemicals-some perhaps mutagenic -- could be created during the complicated processes of fermentation, oxygenation, and precipitation. Although the concentrations of these would most likely be minimal, long-term exposure of skin and lungs to the fluid and vapor could perhaps cause a cumulative and catastrophic effect.

And so, to me, the most logical interpretation of the meager evidence traversing centuries of time is as follows:

The large-scale commercial production of indigo in colonial Louisiana did pose health risks-even to the point of being fatal -- for those employed in its manufacture. On the other hand, cottage production of the dye as practiced, for example, in present-day Mexico-and that was most likely practiced by the early settlers in Cameron Parish -- is entirely safe.

Thus, indigo's infamous legacy seems to be true. The King of Dyestuffs was a malevolent ruler whose reign was tainted with death.

Gary Noel Ross, Ph.D., [(504) 927-8179]
is a collector of natural-dyed textiles.
A Professor Emeritus of Biology from Southern University,
he is Consultant for Educational Programming
for the "Butterflies in Flight" exhibit at the Audubon Zoo in New Orleans.