We have previously shown that just as the labour of an individual workman
 breaks up into necessary and surplus labour, the aggregate labour of the
 working-class may be so divided that the portion which produces the total means
 of subsistence for the working-class (including the means of production
 required for this purpose) performs the necessary labour for the whole of
 society. The labour performed by the remainder of the working-class may then be
 regarded as surplus labour. But the necessary labour consists by no means only
 of agricultural labour, but also of that labour which produces all other
 products necessarily included in the average consumption of the labourer.
 Furthermore, from the social standpoint, some perform only necessary labour
 because others perform only surplus labour, and vice versa. It is but a
 division of labour between them. The same holds for the division of labour
 between agricultural and industrial labourers in general. The purely industrial
 character of labour, on the one hand, corresponds to the purely agricultural
 character on the other. This purely agricultural labour is by no means natural,
 but is rather a product — and a very modern one at that, which has not
 yet been achieved everywhere — of social development and corresponds to a
 very definite stage of the development of production. Just as a portion of
 agricultural labour is materialised in products which either minister only to
 luxury or serve as raw materials in industry, but by no means serve as food,
 let alone as food for the masses, so on the other hand a portion of industrial
 labour is materialised in products which serve as necessary means of
 consumption for both agricultural and nonagricultural labourers. It is a
 mistake, from a social point of view, to regard this industrial labour as
 surplus-labour. It is, in part, as much necessary labour as the necessary
 portion of the agricultural labour. It is also but a form rendered independent
 of a part of industrial labour which was formerly naturally connected with
 agricultural labour, a necessary mutual supplement to the specifically
 agricultural labour now separated from it. (From a purely material point of
 view, 500 mechanical weavers, e.g., produce surplus-fabrics to a far greater
 degree, that is, more than is required for their own clothing.)