Will no one rid me of these tiresome Latin plurals?

The English language has inherited many scientifc words from Latin: a spectrum, an index, a torus, a formula. Then which plural forms should we use: the Latin plurals two spectra, two indices, two tori, two formulae? Or the English plurals two spectrums, two indexes, two toruses, two formulas? The Latin and the English plurals of these words are both considered correct, but the Latin plurals are more widespread. I will nevertheless argue that using Latin plurals is impractical and illogical, and should often be avoided.