WHICH SHALL IT BE?
Jenner died in 1823, and at that date three kinds of virus were in use; first, cowpox from horsegrease or horsepox; second, cowpox; third, horsepox. These of course were subject to inscrutable modification in transmission from arm to arm: it is the distinct sources we have to recognise. A patient intent on vaccination might have said to himself, Which shall it be? Shall I be cowpoxed? or, shall I be horsepoxed? or, shall I be horsepoxed cowpoxed? How such an inquirer would have been answered had he set his perplexity before his medical adviser, I can only conjecture. Probably he would have been rebuked for his intrusion into matters outside his province. The little girl who quenched the scepticism of her comrade with the dictum, “It is so, for ma says so; and if it isn’t so, it is so, if ma says so,” illustrates the manner of rebuff administered to those who pry into professional mysteries. It is for you to pay and for us to think is a formula by no means limited to ecclesiastics.