Even in the tropics, long before refrigeration was invented, raw milk was an essential and safe food source for many cultures. It was regarded as ‘white blood,’ a kind of ‘stem cell’ of foods, and people understood that in trying circumstances, you could live on it exclusively and remain perfectly healthy. After all, just as eggs contain all the nutrients needed to nourish a growing chick, raw milk contains all the nutrients needed to nourish a growing calf; it needs to be a near-perfect food.