It is also worth rehearsing what 0.2 ng l−1 of LPS means in terms of the bacterial equivalents. Watson and co-workers  showed in laboratory cultures that LPS amounted to some 50 fg per cell in a logarithmic growth phase, falling to 29 fg per cell in stationary phase. As remarked previously , this shows at once that LPS contents per cell can be quite variable and that bacteria can shed a considerable amount of LPS at no major harm to themselves. On the basis that 1 mg dry weight of bacteria is about 109 cells, each cell is about 1 pg, so 50 fg LPS per cell equates to about 5% of its dry weight, a reasonable and self-consistent figure for approximate calculations. We shall take the ‘starved’ value of 30 fg per cell. Thus, 0.2 ng l−1 (200 pg l−1) LPS is equivalent to the LPS content of approximately 7 × 103 cells l−1. Most estimates of the dormant blood microbiome (that is derived mainly by dysbiosis from the gut and from the oral cavity as summarized in [5–7]) (some are much greater ) imply values of 103–104 ml, i.e. approximately 1000 times greater. In other words, a bacterial cell need lose only a small amount of its LPS to affect blood clotting in the way we describe here.