I  first heard about the  John Uri Lloyd's  cold extraction still  not too long after I started seriously studying medicinal herbs. Later, I made a pilgrimage to the Lloyd Library in Cincinnati and asked the librarian if she had any detailed information on that extractor. She basically replied,  not much,  which surprised me. Her response made me think I was one of the few that might have ever asked.  That was a number of years ago. Now I see there is more information out there thanks to the Lloyd Library which evidently did more homework since I was last there.   Yet still,  not much critical work has been done so it seems on why the Lloyd's cold still no longer is used. Maybe this page might help clear a few things up?

     First, lets examine why the cold still came into being in the first place. Why was there a need?   In 19th century America, medical practitioners were not a highly admired group. There was much inter-professional bickering and jealousies along with an over-dependence on what may be termed, "heroic" medicine which produced a lot of discomfort in patients. None of it set well with the public. There were basically three sects of formally educated physicians back then, the Allopaths, the Eclectics, and the Homeopaths. The allopaths became what we now consider mainstream medicine--the M.D.s of our current day.  The Eclectics on the other hand evolved out of the American herbal traditions and were formally trained medical doctors that considered and relied on botanical medicine as an important part of their practice. The label, "eclectic" stems from the practice of these medical people using whatever seemed best to produce a successful outcome and more often than not, herbal remedies seemed to work well while the heroic medicine of the MDs, did not. The Eclectics were not tied to any one dogma, nor did they generally favor the harsh realities of heroic medicine i.e. bloodletting, prescribing toxic mineral chemicals like mercury,  antimony, along with  blistering, sweating, purging, induced vomiting, surgery, etc-all main staples of the Allopaths of the 19 th century, the so called: regular Doctors, the MDs. The Eclectics lost out to the Allopaths in the 20th century with their last medical school closing in 1939. The Homeopaths experienced some popularity in the 19th century up unto today. They relied on very dilute concentrations of various orally prescribed substances to stimulate healing in the body, implementing their view that "like cures like".

     How effective was the Eclectic form of practice versus the MDs? Here is an example of some statistics taken comparing the two from competing Hospitals of each in New York, Chicago, Cincinnati, St. Louis, Indianapolis, Springfield, Des Moines, San Francisco, and Atlanta:

Typhoid Fever

    I have a personal interest in this era of American medicine as both my great-great grandfather (Joseph Jones) and his son (Charles Jones) were allopaths (MDs). I often wondered, if I had been in their shoes, would I have gone down their chosen path to go to a regular (allopathic) medical school, viewing the competing Eclectics as unworthy?  From what I know of their practices in subsequent years, I probably would not. I often wish I could have visited with my long ago ancestors to know their reasoning in choosing the allopaths over the eclectics. Joseph went his first year at Jefferson Medical College in Philadelphia then transferred to the Miami Medical College in Cincinnati, Ohio which was also coincidentally, the location of the Eclectic College of Medicine headed by John King. Interestingly, both my ancestral MDs were not happy with their skills as physicians as handed down through family lore. Both were deeply affected by patients they frequently lost and found farming with particularly horse breeding/training much more rewarding. Charles Jones went to Washington Medical College, St. Louis, following in his father's footsteps with another allopathic medical institution.  

     As a modern herbalist, I  tend to study the medical works and practices of the Eclectic sect for guidance on how best to use many herbs, mostly of a domestic variety. There were many anecdotal case histories written up in each state's Eclectic medical journals providing ripe data for us to mine as modern herbal practitioners and thanks to John Uri Lloyd, we also have a lot of scientific data of how best to formulate effective herbal preparations from that era.

     The Eclectic practice of therapeutics can generally be described as evolving in three stages.  From 1830 to 1850, the eclectic practice of medicine seemed to be centered on eliminating fevers and other inflammations of the body by the use of potent purgatives (laxatives) and emetics (induce vomiting) which was the Eclectic's answer to the allopathic bloodletting and mercury therapies of that era. The botanic preparations prescribed during this period were often given in large dosages of foul tasting formulas.

      From roughly 1850 to 1860s, a new movement was forming which involved concentrated dosing which grew out of an 1835 experiment John King did with Podophyllum also known as Mayapple,  a purgative.  King made a concentrated resinous precipitate from a Podophyllum extract that ushered in the concentrate era. Also, concentrated alcoholic tinctures were starting to be marketed. It was this popularity for concentrates that tore the Eclectic movement apart about this time. You have one group viewing concentrates as they could be had from the pharmacies as adulterated inert monstrosities with the opposing group supporting them. In short, this period of Eclecticism was being undermined by pharmacies employing neither standardized formulating processes resulting in varied concentrations nor quality control of the raw materials used in the processes.

   From the 1860s to the 1930s, John Scudder and his "specific medications" bought in a new popularity for the Eclectic movement which involved small doses with pleasant tastes. Scudder brought to the Eclectic practice, the concept of a standardized concentration (16 oz of crude herb per pint or 16 fluid ounces of solvent) along with a quality product, mostly in the form of concentrated tinctures. His specific medications were characterized by tinctures made from fresh herbs without the use of heat, properly gathered at the right time, free of inert properties. Scudder believed that in the majority of cases (a few exceptions) that the fresh herb with juices intact produced the best medicinal tinctures. To safe guard the integrity and potency of these fresh herbal juices, heat must be avoided. Specifics were generally considered to be more concentrated (up to eight times) than the official USP fluid extracts specifications of the times ).  All of these specifics were first formulated by preparing a common tincture from the fresh crude herb and then concentrating.  And it was this concentrating process that Lloyd improved with the invention of his Cold Still Extractor.  Lloyd described his new invention as:  "The object of my invention is an apparatus for making solutions, such as extracts and abstracts, whereby the substance held in solution is not changed by heat, by which the strength of the solution may be changed readily to suit the case, in which the alcohol or other rmenstruum remaining in the waste may be recovered readily for use again."  

Eclectic Deaths %.

Allopathic Deaths %






Diphtheria and Croup

Yellow Fever


All Diseases

The object of my invention is a concentrator in which the evaporation of the solvent is made to take place at the surface while the body thereof is kept cool, which is provided with an efficient and economical means for attaining this latter result.

The herbs or other material .from which an extract 'is to be made is placed in a steeping-tank "A" and steeped or macerated in appropriate menstruum in that tank. The herb and solvent is placed in the steeping tank "A" by removing its cover.

In operation after the steeping process has gone on for the desired time the valve is opened and the solution passes into the concentrating-tank "B", covering the heating-coil "c", which may be heated by means of steam or other heating medium. The evaporation of the solvent, such as alcohol, takes place at the surface of the fluid in the concentrating-tank "B", passes thence up into the pipe "b" and condenser "F", and, when condensed, passes through pipe "f", back into the steeping-tank "A" to be used again for steeping.

The external coil "D", being located just below the heating-coil and being kept cool .by reason of its large exposure of surface to the atmosphere, keeps the liquid below the heating-coil cool, so that the substances held in solution are not deleteriously affected by the heat, while at the same time it affords a sufficient communication between the main body of the fluid in the reservoir "E" and the portion of the fluid near the surface to maintain the uniform it 'of the solution throughout. After the fluid has been concentrated to the extent desired,  it may be drawn off through the discharge-pipe "e" by opening valve "c", which is kept closed during the process of concentrating.

    The above photo is an example of the evolved version of the first apparatus previously described on this page in the Lloyd's 1906 patent. They were widely used in Pharmaceutical manufacturing for a good part of the early 20th century until better processes came along though the need to produce a Scudder type of Specific tincture had long passed. The beauty of the Lloyd Cold Extractor in the late1800s was that though not technically "cold" as the label implies, the Lloyd extractor did keep the delicate botanical solutions much cooler than anything in the past, producing a superior concentrated herbal tincture involving the minimum of heat.

        Today, we can employ low air pressure (vacuum) to do the same thing with even less heat! Lloyd would have been enthralled! John Uri Lloyd did not have the luxury of utilizing low air pressures which we now know can be utilized to lower boiling points! He devised an apparatus that would isolate the heat only to a small portion of the botanical solution, the upper surface, but nevertheless, higher temperatures were present. Boiling points are affected by its temperature and vapor pressure--the lower the vapor pressure, the lower the temperature that is needed. As an example, water boils at sea level at 100°C while one mile up in Denver, it takes 95°C, 5 degrees less heat. The less air pressure, the lower the temperature needed to boil! Configure an extractor that will subject your raw botanical tincture to lower air pressures by using a vacuum pump and you can lower the boiling point of that solution with the bare minimum of heat! One can easily boil water at room temperature, if enough vacuum is applied and room temperatures will not degrade even the most delicate of essential oils and other volatiles!

        So what kind of apparatus can we use to equal or surpass the Lloyd Extractor of old? It can be found in modern "rotary evaporation" technology with the apparatus commonly called a "rotovap".  Every organic lab possesses one, as should every serious herbalist. Food chefs and bar mixologists in their goal to create better, more potent recipes are purchasing rotovaps in droves. Why the common herbalist have ignored its use is a bit perplexing though you will find them in use in the cannabis industry producing quality cannabis oils.

The modern rotovap
The modern rotovap in a t ypical laboratory setting.