Some of his other comments include the following:
1. The Sandia pictures completely agree with my expectation of partially collapsed exosporium. It may be still there but hard to detect in the dry spores. Treatment of the B. subtilis spores with urea helped reveal the exosporium-like layer (A picture from Nature 263, 53 - 54 is on the second of the attached slides). Please notice the similarities with Sandia spores. This technique could be useful to determine the amount of exosporium in Sandia samples. Your calculations present a strong argument that the silicon content is unnaturally high. However, I’m in doubt that the highly variable amount of Si in the samples can be used as a reliable forensic marker on par with genetic ones. The anthrax attack was a deliberate action, and there is nothing surprising to learn that the spores were treated deliberately. Can this conclusion help identify a particular perpetrator?
2. The nature of debris clearly visible in the spore prep is intriguing. It looks quite similar to dry agar from a Petri dish
3. I think you may overestimate the technical difficulty of the siliconization. It may be just a drop of an old-style school glue (liquid glass). A well-developed technology is supposed to give consistent results, but we see a high variability of the Si content, which indicates experimentation with different treatments. In your opinion the perpetrator is primitive and this effectively exculpates Detrick. In my opinion, even at Detrick there could be people with a creative mind who know chemistry beyond written protocols.
4. I don’t know what the FBI has tried for reverse engineering. Did they even consider soluble silicates, not siloxanes? I guess we have to admit that the perp was/is a clever guy. Why should he leave a trace ordering a reagent if it was available from Wal Mart? The person obviously realized the possibility to be traced back and therefore took advantage of his unique knowledge of how to accomplish his task in the most inconspicuous way possible?
5. As I wrote, a familiar example is the drug Simethicone, which is the active ingredient in drugs such as Gas-X. Simethicone is generally available over the counter under many trade names in varying dosage sizes, including: Flatulex, Baby's Own Infant Drops, Gas Relief, Gas-X, Genasyme, Maalox Anti-Gas, Maalox Max, etc. The use of antifoaming agent such as Simethicone will result in detectable Si without other inorganic component. I’m not talking about a paper glue, which is a pure sodium silicate.