All the shares of stock held by any person, in any bank, incorporated by or in pursuance of any law of the government of the United States, are hereby declared subject to taxation, in the hands of the holders of such shares, at the same rate as the shares, or stock, of banks incorporated by or under any law of the Commonwealth of Pennsylvania are now taxable, in the hands of the individual holders of such shares, and at no other or greater rate; that is to say, a tax of three mills upon every dollar of the value of such shares, or stock, shall annually be assessed and collected in the manner hereinafter provided.