ulcers or other running sores, or milk drawn from cows fed unwholesome food, or milk contaminated by being kept in stables containing cattle or other animals and cream from any such milk, or cream in any stage of putrefaction are hereby declared to be unclean and unsanitary milk or unclean and unsanitary cream, as the case may be." Most states have laws which determine the legal standard of milk. Any one selling milk which does not meet this standard is liable to be fined. The laws of most states prohibit the taking of anything from the milk or the adding of anything to it. This prohibits the skimming and watering. Skimmed-milk must be sold as such. +328. Marketing of cheese.+--There are many different methods[138] of selling cheese. Each is adapted to certain conditions and each has its advantages and disadvantages. In cheese sections, the customary method of selling is on the board of trade, which is the meeting of the cheese-buyers and factory salesmen. They meet at a given place at a certain day and hour each week. Every board has its officers. There are different ways in which a board of trade may be operated. In some cases there is a large blackboard divided into columns. In the first column, the salesman writes the name of the factory and the number and kind of cheese offered for sale. At the top of the other columns are the names of the different cheese-buyers. The president usually opens the sale at a stated time and asks that all cheese be placed on the blackboard. When this is done he states that they are ready to receive bids on the cheese. The buyers then write the price a pound they wish to pay opposite each lot of cheese and in the column headed by their names. After all the bids have been received and placed on the board, the presiding officer states that a certain length of time, usually fifteen minutes, will be given the salesman to withdraw his cheese if he does not think a high enough price has been offered; this is indicated by the salesman stepping to the blackboard and erasing the factory name and number of boxes. At the close of the stated time, the presiding officer declares the cheese offered on the board sold to the highest bidder. The purchaser then gives the salesman directions for shipping. Sometimes a board of trade has a committee of one member elected by the factory salesmen and one elected by the cheese-buyers. These two members elect a third and these three constitute the price committee. This committee meets each week and determines what the price shall be. This is known as the ruling. The factory salesmen and cheese-buyers then try to make private sales. By this method no one, except the persons concerned, knows exactly what price is paid for the cheese. Usually, a price above the ruling is paid.