my qualifications for this work are by no means substantial , my time for the pursuit of natural history being sadly curtailed by the demands of my parish , so if i am to persuade it must be with the force of my argument alone , and not through influence or impressive references ... . by no means do i intend any disparagement of those noble creatures under discussion , nor to quarrel with any man who would call them admirable ; their virtues are manifest , and among the highest of these the essential good-humour of their nature , evident in their submitting to the guidance of mankind for the sake of affection , rather than through a compulsion it were quite impossible for any man to bring to bear upon them .