Ewer Pick

Caro s main concern, however, was with the patenting activities of the Berlin-based dye-making firm of Ewer Pick, which had taken out patents for processes that gave the dyes known as methylene blue and auramine. These were original inventions of BASF, and covered by patents, but the Hoechst dyeworks and Ewer Pick had filed patents for different processes. This resulted in cross licensing arrangements between BASF and Hoechst, and, in 1886, the purchase by BASF, for a considerable amount of cash, of the Ewer Pick patents. In addition to his criticisms of speculative patentees, Caro had asked Meldola to undertake laboratory experiments based on one of the Ewer Pick patents. The latter responded ... 

I am much interested in what you say about the speculative patentees. We suffer a great deal from these kind of people here, but not as much in chemical patents as you do. I must confess that I have only made one experiment with the Ewer Pick patent and that was unsuccessful. I did not do the experiment very carefully however and attributed the failure to my carelessness. ... 

In 1889, and almost at the end of his career at BASF, Caro was called upon to act as expert witness in a case of patent litigation in which Ewer Pick attacked the Congo red patent. Some commentators have wondered why Caro was involved in this case, especially since it appeared to have nothing to do with BASF. Thus Herbert Levinstein (1878-1956), who had taken over the Manchester-based dyemaking business of his father, Ivan Levinstein (1845-1916), during World War I, commented in his 1949 Douglas Lecture before the British Society of Dyers and Colourists What interest the BASF had in Caro s last piece of work for them is hard to see . ... 

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