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The invention presented to the Court in Diehr was a “physical and chemical 
process for molding precision synthetic rubber products” where the process steps 
included using a mathematical formula.  The Court held that the invention fit the 
“process” category of Section 101 although mathematical calculations were involved, 
and repeated its observation in Chakrabarty that “courts should not read into the patent 
laws limitations and conditions which the legislature has not expressed.”  Diehr, 450 
U.S. at 182 (internal quotation marks omitted) (citing Chakrabarty, 447 U.S. at 308). 
The Court distinguished a claim that would cover all uses of a mathematical 
formula and thus is an abstract construct, as in Benson, from a claim that applies a 
mathematical calculation for a specified purpose, as in Diehr.  The Court stated that “a 
claim drawn to subject matter otherwise statutory does not become nonstatutory simply 
because it uses a mathematical formula, computer program, or digital computer,” id. at 
187, and explained that the line between statutory and nonstatutory processes depends 
on whether the process is directed to a specific purpose, see id. (“It is now 
commonplace that an application of a law of nature or mathematical formula to a known 
structure or process may well be deserving of patent protection.”  (emphasis in 
original)).  The Court clarified that Flook did not hold that claims may be dissected into 
old and new parts to assess their patent eligibility.  Id. at 189 n.12. 
However, the Court did not propose the “machine-or-transformation” test that this 
court now insists was “enunciated” in Diehr as a specific limit to Section 101.  Maj. op. 
at 10.  In Diehr there was no issue of machine or transformation, for the Diehr process 
both employed a machine and produced a chemical transformation: the process was 
conducted in “an openable rubber molding press,” and it cured the rubber.  In 
2007-1130 
 
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