'Mrs Cossins' was JW's cook and housekeeper. Her husband was JW's butler.
Mrs Cossins was in JW's employment from 1874 to 1879 as cook and housekeeper. Her husband was described as 'an excellent servant' and likewise JW was very complimentary about Mrs Cossins' cooking, describing her as 'one of the best cooks in London', although he alluded to her drunkenness: 'she was good tempered enough - and willing - and honest - if not always strictly sober' (#01499).
In 1876, in a letter to his mother, he complimented her pickles, made according to his mother's recipe (#06564). In 1879 he spoke affectionately of her as 'dear funny old Mrs. Cossins!' He noted that 'little Watts used to say he always liked her when she was very drunk!' (#06686).
Following her employment with JW, she was cook to the sculptor J. E. Boehm, who described her as creating culinary symphonies (#00323).
In 1881 'Mrs Cossins' is recorded as the cook to Henry Lushington, at Aspenden Hall, Hertford. At that point the census gives her name as Caroline, and her status as unmarried, which is curious. The couple may have parted, ot the title of 'Mrs Cossins' may have been an honorary one.
UK census 1881, from http://www.familysearch.org (accessed 2004).