maintained their shepherd character, but when they once passed the site of the present city of Vienna and entered the plateau of Bavaria, they found new physical conditions which caused them to reduce and to separate their herds of large cattle—­an unbroken forest affording little pasture of grass.  Here they found the wild boar subsisting upon the mast of the forest, and him they domesticated out of an economic necessity, to take the place of their larger cattle as a basis of food supply.  Until then they had not been meat eaters, and so had known no necessity for cereals, for milk is a balanced ration in itself.  But this change of diet required them also to take to agriculture and so to abandon their nomad life.

’By reason of the habits of the animal, swine husbandry has a tendency in itself to confine those engaged in it to a more or less sedentary life, but we are about to see how the Celts were compelled to accomplish this important evolution by an even more powerful force.  Meat cannot be eaten habitually except in conjunction with a cereal ... and of all the meats pork is the one which demands this association most insistently, because it is the least easily digested and the most heating of all the meats....  So that is how the adoption of swine husbandry and a diet of pork compelled our nomad Celts to take the next step and settle down to agriculture.’]

[Footnote 131:  This Gallic tomacina was doubtless the ancestor of the mortadella now produced in the Emilia and known to English speaking consumers as “Bologna” sausage.]

[Footnote 132:  The Gaul of which Cato was here writing is the modern Lombardy, one of the most densely populated and richest agricultural districts in the world.  Here are found today those truly marvellous “marchite” or irrigated meadows which owe the initiative for their existence to the Cistercian monks of the Chiaravalle Abbey, who began their fruitful agricultural labours in the country near Milan in the twelfth century.  There is a recorded instance of one of these meadows which yielded in a single season 140 tons of grass per hectare, equal to 75 tons of hay, or 30 tons per acre!  The meadows are mowed six times a year, and the grass is fed green to Swiss cows, which are kept in great numbers for the manufacture of “frommaggio di grana,” or Parmesan cheese.  This system of green soiling maintains the fertility of the meadows, while the by-product of the dairies is the feeding of hogs, which are kept in such quantity that they are today exported as they were in the times of Cato and Varro.  There is no region of the earth, unless it be Flanders, of which the aspect so rejoices the heart of a farmer as the Milanese.  Well may the Lombard proverb say, “Chi ha prato, ha tutto.”]

[Footnote 133:  Virgil (Aen.  VII, 26) subsequently made good use of this tradition of the founding of Lavinium, the sacred city of the Romans where the Penates dwelt and whither solemn processions were wont to proceed from Rome until Christianity became the State religion.  The site has been identified as that of the modern village of Practica, where a few miserable shepherds collect during the winter months, fleeing to the hills at the approach of summer and the dread malaria.]