PREFACE.

another, obstinately biased against the subject of inquiry and little inclined to offer their help in investigating the relevant facts. The members of the medical profession, although perhaps the ones most interested in the ultimate result of the inquiry, distinguished themselves throughout by their bitter opposition to the new discovery, driven by very obvious, though not very generous or even respectable, motives.

The greater part of our scientific prejudices undoubtedly arises from mental bias—from the partial or inadequate nature of our previous investigations. Being unable to comprehend the entirety of nature's diverse phenomena, and therefore confining our attention to a small portion of those most familiar to observation, we nevertheless proceed, based on this limited view, to form our judgment regarding the totality of her laws. This premature and therefore narrow process necessarily leads us to a partial, unsatisfactory, deceptive, and imaginary conception of the powers and operations of nature, which we feel ourselves unable or unwilling to embrace in their full scope or in the infinite variety of her manifestations. Accidental circumstances also frequently direct the attention of mankind, in every age, toward a specific line of inquiry, resulting in the neglect of almost every other field of knowledge; and,