Priming with lactose

This is a rather strange one. Just about the time that Milk Stout was being invented, someone proposed a different use for lactose: in priming.

This use was proposed by a Mr. J. Melhuish.\

Priming for Malt Liquors.
The object of the inventor is to produce a priming for malt liquors which will not lose its characteristic flavour in course of such time as the beer is proposed to be kept in stock. In ordinary practice the cane or invert sugar, or glucose employed, speedily loses its sweetening power and becomes changed into other products, thus rendering it impossible to say exactly what degree of sweetness may remain at any given time after brewing is completed, say for instance three months. To obviate this uncertainty the inventor, Mr. J. Melhuish, lecturer on dietetics. Glasgow, instead of using sugar or glucose, employs as priming agent, lactose, or milk sugar, the quantity recommended being eight pounds dissolved in its own weight of boiling water, to each barrel. It is stated to be permanent in character, and not to deteriorate in regard to flavour except by the agency of lactic ferments, which have already been destroyed during the fermentation of the beer.
The Brewers' Journal vol. 45 1909, March 15th 1909, page 185.

To me, it makes absolutely no sense. Anf implies that Mr. Melhuish didn't really understand the purpose of priming. He seems to have assumed that it was intended to add a permanent degree of sweetness. Which, obviously, would work better with unfermentable lactose than with derivations of sucrose. Whereas, in reality, the principal function of primings was to add fermentable material to bring the beer into condition in the cask.

Mr. Melhuish also made the assumption that no yeast could ferment lactose. But that's not true. Some types of Brettanomyces can. If you left a beerr for several months, then a Brettanomyces could kick in and alter the flavour profile, anyway.

Overall, it sounds like a crap idea. Which is probably why it never became popular. Though I can think of an example of its use: at Whitbread. In the 1930s, when they brewed Mackeson Milk Stout, they didn't add the lactose in the boil but at racking time as prinings.