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Return to: Two Views on Helmont's Willow Experiment

Rebuttal to Allchin's Comments in the October 2003 Pantaneto Forum

I am disappointed that Mr. Allchin once again refused to address the factual errors I pointed out (Hershey 2003b) but instead used his October 2003 comments in The Pantaneto Forum (Allchin 2003) to insult me, misquote me, contradict himself and make more historical errors. I will go through Mr. Allchin's comments one by one but first, let me state my central theme:

Mr. Allchin (1993, 2000a, 2000b, 2002b) has presented a fabricated, inaccurate version of the historical context for Helmont's experiment because he did not base his context on the ample historical literature on Helmont. Table 1 contrasts Mr. Allchin's fabricated historical context and the actual historical context based on the historical literature. Mr. Allchin then used his innaccurate fabrication to harshly and unfairly criticize Hershey (1991) and never even heeded the Anonymous Reviewers' Comments (Anonymous 1993) for his original manuscript. Classroom use of Allchin's (1993, 2000a, 2000b, 2002b) recommendations is fraught with problems.

1. Mr. Allchin is correct that he published the second version of his article criticizing Hershey (1991) in the Journal of College Science Teaching (JCST), a journal of the National Science Teacher's Association (NSTA) . The JCST editor apparently saw merit in my comments on Allchin (2000a) because he published them (Hershey 2002). Ironically, the NSTA agrees with Hershey (1991) in their classroom discussion of Helmont because they point out that Helmont's experimental data did not justify his conclusion. Most of the many dozens of textbooks and websites I have seen that discuss Helmont's willow experiment do mention that Helmont made a conclusion that did not follow from his results. His conclusion was as inappropriate in 1648 as it is today.

If article pedigree makes a difference, Hershey (1991) was published in the American Biology Teacher, a journal of the National Association of Biology Teachers. Also, on the subject of article pedigrees, the Plant Science Bulletin, a journal of the Botanical Society of America, published my article on "Misconceptions about Helmont's willow experiment." (Hershey 2003a). It uses the historical literature to discuss in greater detail many of the fabrications in Allchin (1993, 2000a).

Given Mr. Allchin's concern for "historical context" and the pedigree of his article, one wonders why he did not mention that the first version was published in 1993 in Bioscene under the title "Reassessing van Helmont, Reassessing History." Perhaps it is because the Bioscene editor also took the unprecedented step of also publishing the Anonymous Reviewers' Comments (Anonymous 1993) for Allchin (1993). Among other things, the anonymous reviewers (Anonymous 1993) asked Mr. Allchin to include "references to the professional history of biology literature ... on van Helmont" and "But given his criticism, shouldn't the author [Allchin] provide us with a discussion about how to actually use his richer historical perspective in a real classroom situation?" They also asked "Can't we use the case to stimulate class discussion about how modern scientists - or the students themselves - might design experiments?"

Mr. Allchin (2002a) claimed he never saw the reviewers' comments which I find impossible to believe because they were referred to at the end of Allchin (1993). Most authors read their published articles, and the publication of anonymous reviewers' comments is so rare, so unexpected, that the Bioscene editor or colleagues would have undoubtedly spoken to Mr. Allchin about them. Mr. Allchin certainly knew about the anonymous reviewers' comments before May, 2002 when he mentioned them (Allchin 2002a). Thus, Mr. Allchin was aware of them in time to correct Allchin (2002b) in the July, 2002, Pantaneto Forum. Of course, history will record that Mr. Allchin did not use them or (Hershey 2002) to correct the major errors and deficiencies in Allchin (2002b).

2. Mr. Allchin implies that he referenced Helmont's original work, and I didn't. The reality is that Hershey (1991) had an English translation of Helmont's entire description of his 1648 willow experiment. All four versions of Allchin (1993, 2000a, 2000b, 2002b) contained no citations to the historical literature on Helmont except Hershey (1991) and a 1965 (Allchin 1993) or 1969 (Allchin 2000a, 2000b, 2002b) introductory biology textbook that Mr. Allchin was also criticizing. Given the publisher, Addison-Wesley, I assume it was a high school biology textbook.

While it is true that Mr. Allchin tried to give a reference to Helmont's original work in JCST (Allchin 2002a) he actually got it wrong. He gave the title as "Works". The actual title of the 1664 book is Oriatricke, or Physick Refined (Pagel 1972). How can an historian supposedly so concerned with correct historical context be so sloppy, again and again? Allchin (1993, 2000a, 2000b, 2002b) even has Helmont's nationality wrong. Helmont was Belgian not Dutch (Table 1).

It is ironic that Mr. Allchin referenced the 1664 English translation of Helmont's experiment yet later criticized me for including a 1666 quote by Robert Boyle because it was 18 years after Helmont's original publication. If Mr. Allchin really wanted to maintain the historical context, why isn't he reading and citing the original 1648 version?

3. Mr. Allchin keeps emphasizing that historical context is so important and refuses to address my point that his historical facts are wrong. A dictionary will confirm that context is merely "the set of facts or circumstances that surround a situation or event". Thus, if the facts are wrong, the context is wrong.

4. As the only example of his new insult, "Hershey's present-oriented approach to history" Mr. Allchin mentioned my citing of Robert Boyle's 1666 criticism of Helmont's 1648 experiment. That is not only illogical, it strikes me as bizarre. In 2003, how can 1666 be considered the present? If you tell students that Helmont published his experiment in 1648 and Boyle disproved Helmont's conclusion in 1666 by using an astute observation on the requirement of manure to maintain crop yields, they can see the chronology. What is wrong with that?

How many people actually repeated Helmont's experiment in the 1600s? Boyle did not as described under item 5 below. Most scientists interested in Helmont's hypothesis turned to Bacon-type experiments which involved water culture (Bacon 1627, Webster 1966). Water culture experiments were much easier and more accurate. There was no need for laborious and inaccurate drying and weighing of soil and separation of roots from soil. In 1770, Antoine Lavoisier reviewed the literature on experiments that purported to show plants were formed from water alone (Nash 1957). He apparently found at most one Helmont-type experiment that did not make the fatal error of using water of "doubtful purity" (Nash 1957). Lavosier considered only Helmont's 1648 experiment and an experiment by Eller to have avoided the fatal error by using rain or distilled water. However, Eller sounds like a water culture experiment based on the brief description in Nash (1957) which mentions concerns about Eller's "water container", but I cannot be sure. Relying on Lavosier's review of the literature as reported by Nash (1957) it seems that Helmont's experiment may actually have been repeated only once or not at all between 1648 and 1770! Sorry, but if you didn't grow your plant in a pot of soil and water it with rain or distilled water as Helmont did, you were not doing a Helmont experiment.

5. Mr. Allchin implied that Helmont's experiment inspired Robert Boyle to repeat it. However, had Mr. Allchin checked the historical literature, he would have discovered that Boyle did his experiments before he knew of Helmont's experiment (Hoff 1964). Therefore, Boyle did not repeat Helmont's experiment. Boyle, like Helmont, apparently got the idea from Nicholas of Cusa's 1450 book (Hoff 1964, Krikorian and Steward 1968). If Hoff's (1964) proposed chronology is correct, Boyle may have even completed the first of his Nicholas of Cusa experiments before Helmont first published his version.

Mr. Allchin's (2003) calculator must have been broken when he said that Boyle's 1666 criticism of Helmont's experiment was "over two decades later." Helmont's experiment was first published in 1648 so that's only 18 years later. Helmont's experiment was not translated into English until 1662 by John Chandler (Krikorian and Steward 1968). Thus, a 1666 rebuttal by Englishman Boyle could be considered contemporary given the slow pace of scientific progress and communication in the 1600s. Insights and experiments often were not published until years after they were initially made. Here Mr. Allchin misrepresented the historical context by apparently doing what he accused me of, using a "present-oriented approach to history."(Allchin 2003). Our fast-moving, publish or perish science is very different from the slow pace of science in the 1600s.

6. To answer Mr. Allchin's questions about Helmont and gases. Helmont made several sound observations and experiments with gases, notably carbon dioxide, which he called gas sylvestre (Pagel 1972). He determined that when he burned 62 pounds of oak charcoal, he obtained 61 pounds of carbon dioxide and one pound of ash (Leicester and Klickstein 1963). He recognized other sources of carbon dioxide such as the gas that was found in mines, the bubbles in wine and belches (Pagel 1972). In contrast, most of Helmont's ideas on gases he simply fabricated. They were not based on observations or experiments so were not scientific. During his experiments Helmont poisoned himself with carbon monoxide so perhaps some of his unscientific ideas were the result of brain damage caused by carbon monoxide. Irregardless, Helmont's unscientific ideas on gases are not really of interest in an introductory biology course which was the context of Hershey (1991). Even the brief discussion of Helmont's ideas on gases in Allchin (2002a) would be totally inappropriate for an introductory biology course and would totally confuse most biology teachers. Mr. Allchin does not seem to understand the context of introductory biology courses.

7. Mr. Allchin found my critique on Helmont to be an "anachronism." As a self-appointed 'history-cop' I would appreciate if Mr. Allchin would use his vastly superior historical knowledge to provide his 'legal' method to teach about Helmont's experiment. What is a biology teacher supposed to do for the situation Allchin (2002b) described. i.e. "Contemporary students are sometimes even guided to repeat this lesson for themselves, albeit on a smaller scale, using radish plants, whose weight change can be observed in weeks rather than years." The Bioscene reviewers (Anonymous 1993) also asked Allchin to provide such details.

Here is a scenario of a science fair judge using Allchin's (1993, 2000a, 2000b, 2002b) recommendations to judge a student project on Helmont's experiment.

Speaking of anachronism. I find Mr. Allchin's (1993, 2000a, 2000b, 2002b) harsh critique of the Helmont discussion in a 1965 or 1969 biology textbook to be an anachronism because 1965 and 1969 textbooks are long obsolete.

8. Mr. Allchin contradicts himself by saying that "But nothing is gained by applying modern standards critically to an earlier case based on different norms." but then cites Allchin (2001) where he states "Rather, past error - properly documented - is a form of negative knowledge. As such it may even productively guide further research....One significant task of science, then, is to catalog and identify potential errors." That is exactly what I was doing in Hershey (1991), which used a critique of Helmont's experiment to teach experimental design, execution and analysis to introductory biology students in high school and college. Hershey (2003a) lists more of the lessons from Helmont's experiment.

9. I think it is ridiculous for Mr. Allchin to imply that I practice "pseudohistory" when he does not provide any literature citations to support his fantasy version of the historical context for Helmont's willow experiment. I think that makes Mr. Allchin the pseudohistorian (Table 1).

10. Mr. Allchin asks that we try to understand Helmont and "It would be valuable indeed to understand how van Helmont could have isolated a substance we now call carbon dioxide and yet reasonably failed to recognize its role in the tree growth he also studied."Hershey (2003a) provided an answer to those questions. Helmont was such an adherant to the theory that water was the primal substance that he ignored several pieces of contrary evidence and made a conclusion that was not fully supported by his data simply to advance his argument. In other words, Helmont was not a very good scientist in this case because he was not objective. He set out to prove a particular hypothesis, not test the hypothesis. This is a valuable lesson for science students when they conduct their experiments.

Mr. Allchin is misrepresenting Hershey (1991). I was not as Mr. Allchin stated "Merely profiling van Helmont's flaws and/or faulting him." I wouldn't have written Hershey (1991) at all if I didn't consider Helmont's experiment to be worth remembering and useful for teaching important lessons about biology. Mr Allchin won't acknowledge the fact that Helmont made an excellent choice by using rain or distilled water in his experiment for a very good reason (Table 1). Nor does Mr. Allchin want to recognize Helmont's excellent experiment indicating that dry plant matter was composed largely of carbon dioxide gas (Table 1). I was objectively considering Helmont's strengths and weaknesses. I find that idealizing of scientists or their experiments is artificial and undesirable. For example, Gabriel and Fogel (1955) idealize Helmont's willow experiment saying it was "an epitome of scientific method" without noting any of its weaknesses.

The history of science certainly confirms that nobody is perfect, and that many breakthroughs were overlooked for years or decades. I think recognizing scientists, like Boyle, whose insights or experiments allowed them to dismiss a prevailing theory about a century before it was more widely abandoned is worth noting. Just because such pioneers were overlooked in their own time is no reason to overlook them when looking back in time.

11. Mr. Allchin's plea that "One must get beyond simplistically labeling right and wrong, hero and fool." is the height of hypocrisy given how he has seemed obsessed with repeatedly and harshly criticizing me and my 1991 article (Allchin 1993, 2000a, 2000b, 2002a, 2002b, 2003). Mr. Allchin characterizes me as a "fool" for Hershey (1991). However, Allchin () then compliments me for my article on the history of Ward's invention of the terrarium (Hershey ). So Mr. Allchin even uses the hero-fool technique on me!

12. Mr. Allchin said he meant his adaptation of the familiar Biblical passage to "plants do not live by water alone" to be ironic. However, I fail to see the irony. The Biblical passage, "man does not live by bread alone", means that people have spiritual needs, not just physical needs. Helmont's experiment had nothing to do with the spiritual needs of plants. On the Mad Scientist Website I routinely field student questions on the pseudoscientific beliefs that plants respond to music, have feelings or respond to talking or prayer. Such a quote might encourage those kind of misconceptions.

I consider it unwise to mix religion and biology in such a cavalier manner because some people who believe in a literal interpretation of the Biblical creation story have interfered with the teaching of biology in USA schools for far too long. That is why I didn't appreciate that quote misattributed to me. I believe some people might even consider Mr. Allchin's quote to be irreverent.

I didn't realize Mr. Allchin was a fan of irony. Perhaps he intended the titles of his articles to be ironic. "Reassessing van Helmont, Reassessing History" Allchin (1993) is certainly ironic given that Mr. Allchin rewrote history with his fabricated historical context on Helmont's experiment. "How NOT to Teach History in Science" (Allchin 2002b) is also ironic because Mr. Allchin's fabricated historical context unsupported by the historical literature is exactly how NOT to teach about history (Table 1).

I also find it ironic that Mr. Allchin (2003) apologized for misquoting me but then misquoted me again saying I used the word "contemporary" which does NOT appear in my Pantaneto Forum comments (Hershey 2003b).

I also find it ironic that although I lack any college degrees in history, I am the one citing reference after reference on Helmont from history journals (Hershey 2002, 2003a, 2003b) while Mr. Allchin the historian (1993, 2000a, 2000b, 2002b) cites none of the history literature on Helmont.

13. Mr. Allchin's last sentence is really irrelevant. Again Mr. Alchin seems to be implying that by reprinting his article, The Pantaneto Forum is somehow endorsing it. The Pantaneto Forum also found my criticisms of Allchin's article to merit publication.

In closing, I still find it shocking that a Ph.D. historian would not bother to read the historical literature on Helmont but just fabricate the historical context (Table 1) and use it to harshly and excessively criticize a nonhistorian again and again and again and again. If an undergraduate submitted Allchin (1993) or the Helmont sections of Allchin (2000a, 2000b, 2002b) as a term paper, I think it would get an F for fabrication of facts and failing to cite any of the historical literature. I am appalled that a Ph.D. historian employed by the University of Minnesota would publish such an incompetent article once, much less in three refereed journals. The three journal editors who published Mr. Allchin's article should be ashamed. I also find the tone of Mr. Allchin's criticisms of me and my work to be bullying, condescending and highly unprofessional. If Mr. Allchin does not like my approach for teaching about Helmont, fine. Let him 'put up or shut up' and present his approach for teaching about Helmont in a real classroom, something he has yet to do despite a request by the reviewers of his first article (Anonymous 1993).

Literature Cited

Allchin, D. 1993. Reassessing van Helmont, reassessing history. Bioscene 19(2):3-5.

Allchin, D. 2000a. How not to teach historical cases in science. Journal of College Science Teaching. 30:33-37.

Allchin, D. 2000b. How NOT to teach history in science. Sociology, History and Philosophy of Science Resource Center.

Allchin, D. 2001. Error types. Perspectives on Science 9:38-59.

Allchin, D. 2002a. Two views on Helmont. Journal of College Science Teaching. 31:425.

Allchin, D. 2002b. How NOT to teach history in science. The Pantaneto Forum. July.

Allchin, D. 2003. Reply by the Author to David Hershey’s comments. The Pantaneto Forum. October.

Anonymous. 1993. Anonymous reviewers' comments on reassessing van Helmont, reassessing history. Bioscene 19(2):30.

Bacon, F. 1627. Sylva Sylvarum. London: J. Haviland.

Hershey, D.R. 1991. Digging deeper into Helmont's famous willow tree experiment. American Biology Teacher 53:458-460.

Hershey, D.R. 2002. Two views on Helmont. Journal of College Science Teaching. 31:424-425.

Hershey, D.R. 2003a. Misconceptions about Helmont's willow experiment. Plant Science Bulletin 49:78-84.

Hershey, D.R. 2003b. Comment on Douglas Allchin's "How Not to Teach History in Science" The Pantaneto Forum. October.

Gabriel, M.L. and Fogel, S. 1955. Great Experiments in Biology. Englewood Cliffs, NJ: Prentice-Hall.

Hoff, H.E. 1964. Nicolaus of Cusa, van Helmont, and Boyle: The first experiment of the renaissance in quantitative biology and medicine. Journal of the History of Medicine and Allied Sciences, 19, 99-117.

Krikorian, A.D. and Steward, F.C. 1968. Water and solutes in plant nutrition: With special reference to van Helmont and Nicholas of Cusa. BioScience, 18, 286-292.

Leicester, H.M. and Klickstein, H.S. 1963. A Source Book in Chemistry 1400-1900. Cambridge MA: Harvard University Press.

Nash, L.K. 1957. Plants and the Atmosphere. pp. 323-426. Volume 2.IN: Conant, J.B. and Nash, L.K. (eds.). Harvard Case Histories in Experimental Science. Cambridge, MA: Harvard University Press.

Pagel, W. 1972. Helmont, Johannes (Joan) Baptista van. pp. 253-259, vol. 6. IN: Gillespie, C.C. (ed.). Dictionary of Scientific Biography. New York: Scribner.

Webster, C. 1966. Water as the ultimate principle of nature: The background to Boyle's Sceptical Chymist. Ambix, 13, 96-107.