Feeling Blue

General Augustus James Pleasonton was always colourful, and in more ways than one.

After a long military career, including being promoted to Brigadier General of the Pennsylvania military in 1861, the troops he commanded helped defend the city of Philadelphia.   Never as prominent as his younger brother Alfred who served as a general in the Union Army, Augustus Pleasanton retired from the military after the Civil War to practice law and, in his spare time, to pursue his own private scientific experiments.  Though never trained as a scientist (he was educated at West Point), Pleasonton developed a fascination for the effect of light on the growth of both plants and animals.  Considering the blueness of the sky, he concluded that blue light was necessary for health due to the electromagnetic currents induced by light.

While research into the possible effect of coloured light on plants and animals had already been published in Europe, it was still considered fringe science by most.   Pleasanton decided to conduct a series of experiments using panes of blue and violet glass and measuring the impact of coloured light on grapevines.    He began by building a cold grapery, 84 feet long and 26 feet wide on his farm near Overton, Pennsylvania.    To test the effects of blue glass, Pleasonton alternated panes of blue and transparent glass so that coloured light would hit every plant in the building at least once during the course of the day.     He then planted twenty varieties of cuttings and carefully measured their growth.

Pleasonton reported that the blue and violet light had an enormously healthy effect on his grapevines and led to a large harvest of grapes.   Not only that, but insects that normally attacked grape leaves were absent and visitors were reportedly amazed by his results.   One visitor reportedly told him that he had never seen grapevines grow so large.  Word of mouth spread about Pleasonton's success with growing grapes and the "blue glass" craze was born.   While skeptics were inclined to be suspicious, the demand for coloured glass led to blue glass graperies being built in many states with Pleasonton receiving letters of praise and reports of other people having similar success.

Encouraged by his new-found fame, Pleasonton decided to see if he could get the same results with animals.    Constructing a piggery with a glass roof, he devised an experiment with his pigs being raised under  blue and transparent glass panes in the same ratio as with his grapery.    As Pleasonton reported,  four pigs were raised under blue glass and four were raised under transparent glass.    When the pigs were weighed on March 4, 187o, he triumphantly concluded that pigs raised under blue light glass had gained more weight.    While the weight difference was not great (on average, the blue-light pigs were only about twelve to thirteen pounds heavier), Pleasonton reported that his experiment was a success.  

Not only did he report that the pigs raised under blue glass grew larger and more rapidly than the control pigs, but he also claimed that blue light had amazing healing properties.   According to Pleasonton, a weakling bull calf that he claimed was on the verge of dying actually improved under the blue light and was soon the same size as any other calf that age.     Testing his blue glass effect on a pet canary that was ill caused it to recover far more quickly than anyone expected.    Another experiment involved treating an arthritic army mule that had been deafened by cannon fire.    The mule reportedly regained its hearing along with having full mobility restored.   All of Pleasonton's enthusiastic reports led to more blue glass houses being built across the United States.   Even in Europe, silkworm producers were reporting that silkworm production was being radically enhanced by the blue glass effect.

Not surprisingly, the blue glass craze also extended to treating human diseases as well.   Men and women gave enthusiastic reports about how sitting under blue glass cured diseases such as chronic rheumatism.   Children suffering from terminal medical conditions also got better after receiving the blue glass treatment.    Encouraged by what he believed to be a radical medical discovery, Augustus Pleasonton patented his blue glass concept in 1871.   That same year saw Pleasonton presenting his findings to the Philadelphia Society for the Promotion of Agriculture.    His lecture was modestly titled, "The influence of the blue ray of the sunlight and of the blue color of the sky in developing animal and vegetable life, in arresting disease and in restoring health in acute and chronic disorders to human and domestic animals.

In his lecture, Pleasanton suggested that the unusually blue sky found at the Equator accounted for the lush jungle growth found in equatorial countries.   He also argued that the green colour in a plant's leaves allows blue light to be absorbed by plants which merges the blue with the yellow radiation taken from the earth.   After the plant blossoms and forms seeds, the blue in the leaves is eliminated and the plant absorbs carbon causing it to become brown and die (brown being seen by Pleasanton as a mixture of yellow and black).   For that reason, blue is the colour of vitality and yellow is the colour of decay and death.   General Pleasanton also argued that blue light stimulated magnetism and electricity (both of which were in scientific vogue at the time).    During the early spring when the sky is bluest, the earth is stimulated to generate carbon and oxygen, thus promoting plant growth. 

After his lectures were finally were finally published in 1876, the book (which was printed in blue ink) helped promote the blue-glass craze.   Unfortunately, the critics were less enthusiastic.  In 1877, Scientific American was obliged to print a detailed rebuttal explaining that blue light had no more virtue than any other kind of light.    Another rebuttal printed in the Philadelphia Medical Times in 1875 even went so far as to examine Pleasanton's original research setup.   In a rather effective example of skeptical journalism, the reviewer pointed out that the two pig sties that Pleasanton used hardly represented a truly objective test of the health benefits of blue glass.   Not only was the "control" sty smaller than the blue glass sty,  butit was also more exposed, dirtier, and wetter.    While Pleasanton praised the health value of blue glass, all that his experiment demonstrated was the value of simple hygiene.    As for his grape experiments, the lack of any kind of a double-blind setup make Pleasanton's findings almost worthless.

Within just a few years, the blue glass craze faded and the world moved on to other interests.   Augustus Pleasanton died in 1894, still insisting that he had made a valuable discovery that the world failed to appreciate.    If Pleasanton's blue glass is remembered at all, it is as a curious example of how new fads can spring up almost overnight and fade just as quickly.  All that it seems to require is a credible source, a plausible message, and the prospect of a better future.  

In the immortal words of Marcello Truzzi, "An extraordinary claim requires extraordinary proof."




Related Stories

  • The Return of Dr. Fox
  • Protecting the Troops
  • When Summer Wouldn't Come (Part 2 of 3)


The information provided on the PsyWeb.com is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her health professional. This information is solely for informational and educational purposes. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Neither the owners or employees of PsyWeb.com nor the author(s) of site content take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading this site. Always speak with your primary health care provider before engaging in any form of self treatment. Please see our Legal Statement for further information.

PsyWeb Poll

Are you currently taking or have you ever been prescribed anti-depressants?
Total votes: 3979