Now Smith proceeds to a further analysis of the mutual relations of these categories and of how they change in the course of the social process, in production and circulation--in the reproductive process of society. He emphasises here a radical distinction between fixed and circulating capital from the point of view of the society: 'The whole expense of maintaining the fixed capital must evidently be excluded from the neat revenue of the society. Neither the materials necessary for supporting their useful machines and instruments of trade, their profitable buildings, etc., nor the produce of the labour necessary for fashioning those materials into the proper form, can ever make any part of it. The price of that labour may indeed make a part of it; as the workmen so employed may place the whole value of their wages in their stock reserved for immediate consumption. But in other sorts of labour, both the price and the produce go to this stock, the price to that of the workmen, the produce to that of other people whose subsistence, convenience and amusements are augmented by the labour of those workmen.'[73] Here Smith comes up against the important distinction between workers who produce means of production and those who produce consumer goods. With regard to the former he remarks that they create the value--destined to replace their wages and to serve as their income--in the form of means of production such as raw materials and instruments which in their natural form cannot be consumed. With regard to the latter category of workers, Smith observes that conversely the total product, or better that part of value contained in it which replaces the wages, the income of the workers together with its other remaining value, appears here in the form of consumer goods. (The real meaning latent in this conclusion, though Smith does not say so explicitly, is that the part of the product which represents the fixed capital employed in its production appears likewise in this form.) In the further course of our investigation we shall see how close Smith has here come to the vantage point from which Marx tackled the problem. The general conclusion, however, maintained by Smith without any further examination of the fundamental question, is that, in any case, whatever is destined for the preservation and renewal of the fixed capital of society cannot be added to society's net income.