The author delivers a readable account of the history of botany and modern ethnobotany in which a wide variety of fascinating subjects are discussed.
This book illustrates the drawbacks of a perspective that is too narrowly focused on microbiology and organic chemistry to reach explanations about medicines, cures, toxins, and plant evolution at the expense of more tenable, holistic perspectives that take phytochemical interactions into consideration.
Time and time again throughout this work it is apparent that plants and what the author defines as "plant medicines" (i.e. synthetic drugs derived from plants) are valued only to be analyized in the laboratory and broken down into their constituent compounds. Though praise for indigenous traditional knowledge of plants is found throughout the book, it appears to be shallow lip service for in the last few pages the author states, "Some firmly believe that traditional healers know more than oncologists and cardiologists and shamanic huts surpass hospital wards." The context makes it clear that the Harvard professor disdains those who would opt for the "shamaic huts."
In several instances the author selectively mentions the drawbacks of using herbs and whole plant medicines (e.g. variable potency and toxicity) without bothering to point out that use of highly concentrated synthetic drugs carry unique risks and dangers not usually encountered with the use of "crude" plant medicines. Indeed, the process of identifying useful plants, finding active compounds and synthesizing these compounds seems to almost be taken for granted by the author as the only intelligent way plants can be used as medicines. At times the authors' failure to present an honest comparison of the drawbacks as well as the strengths of modern medicine and herbalism borders on hypocricy. At the very least a double standard is used as the author uses scare tactics and low brow innuendo to inflate and sensationalize the dangers of herbalism while failing to note any inherent risks in modern medicine or drugs. For instance, the author selectively cites only a few of the most dangerous herbs to imply that they are all dangerous or require regulation. In the exact same vein, the author refers to herbalists from the past as "quacks" and "charlantans" failing to note the obvious fact that the state of medical knowlege in the 21st century is slightly more advanced in some ways than it was two hundred or more years ago. Collectively speaking, this line of reasoning follows of trend of many modern scientists who believe that the assembly-line corporate "health care systems" we have today are far superior to any form of medicine that involved interaction between human beings as opposed to pronouncing a person's state of health based on a single lab test.
The author presents a weak thesis that "secondary compounds" found in wild plants are poisons whose purpose is to discourage herbivores. If that was the case then why have so many plants developed mechanisms to attract herbivores to feed on them? In many cases, such as with many types of flowers, the plant cannot reproduce without the aid of herbivores to assist with the vital processes of seed pollination and dispersal. This thesis begins to look even more ragged as the author considers the example of THC as a "toxin" that decreases an herbivore's chance of survival when in fact many types of naturally occuring hallucinogenic compounds have been shown to actually increase sensory perception and visual acuity in mammals, making their survival against predators more likely rather than less. The author appears to prefer the view that plants and animals are engaged in mutual, interneccine combat rather than sets of complex and often symbiotic relationships. This follows the pattern of the author's fixation upon toxins and "secondary compounds."
The author goes on to exaggerate the risks of poisoning by herbs contaning pyrrolizidine alkaloids, conveniently ignoring the fact that research on the subject is inconclusive. The author worries about the fact that the effective dose and toxicity is likely to vary from plant to plant without mentioning the fact that many common, very widely used over the counter drugs like aspirin can be toxic and even fatal in relatively small doses. Nor does she note that many powerful drugs have an effective dose that is quite close to toxic dose (low LD50). In one instance, the author claims that THC is some sort of plant toxin defense mechanism against herbavores in the hemp plant. This is clearly absurd since THC is typically present in hemp in concentrations of 3% or less and since extremely high doses of it are necessary to be toxic to animals. Furthermore, THC causes an increase in appetite, so why would that discourage animals from eating plants that contain it? This example causes me to doubt that this author understands what a toxin is. Either that or the author is using an extremely selective and highly misleading definition of toxicity in order to frighten and confuse the readers about the nature of herbs, herbalism and plants.
Never the less Sumner does an excellent job of presenting the case for ecosystem preservation, the legal aspects of creating and finding new drugs. The author also outlines contoversies surrounding the exploitation of indigenous healers and describes ways to remedy these situations that can provide equitable soluions for local people as well as drug researchers. Additionally, Sumner provides interesting discussion about seed banks and their role in preservation and research and the history of herbarium collections. The authors' well stated explanation of the importance of maintaining genetic diversity in plants will enlighten readers.
Unfortunately readers will need to be skeptical at all times as this author has a strong bias against herbalism and traditional folk healing. This book could be a case study of how "science" is invoked to establish intellectual authority, yet exaggerated claims are made and poorly argued, psuedo reasoning, scare tactics, innuendo and name calling are substituted for established facts, thorough research and honest treatment of opposing points of view.
Readers need to be wary of people who say they have "science" on their side. That isn't a real argument. Research results and statistics don't "lie" but they are often inconclusive and easily manipulated. Citing research is not enough to establish truth. The relevence of the research and its limitations need to be presented. All the evidence for and against something should be presented.