Some descent is required from ordinary scientific observation to the level where this question is discussed. From the germ-cell, we pass down to an albuminous substance spread over the ocean-bed, said to have life, or we descend to microscopic organisms, such as bacteria; and a step lower down still, we are introduced to the question whether in water passed through the boiling process so as to guard against the presence of germinal forms, we may not witness the origin of life. The question so raised had additional interest because of the bearing it might have on the first appearance of life in the history of this world. This interest was shared on both sides, by those who held that creation is a conception not only alien to scientific thought (which it may well be[E]), but inconsistent with it; and by those who regarded creation as the only conception adequate to meet rational requirements. The question had at the same time a direct practical interest connected with public health, on account of its bearing upon the diffusion and vital tenacity of spores or germinal forms capable of spreading contagious disease.[F] The controversy on this subject was at its height in the years 1876, and 1877, having a large amount of most careful and difficult experiment devoted to it. The result has been a valuable addition to scientific knowledge as to the vitality of germinal forms, and a quietus to theories as to "spontaneous generation." The direct object placed before the scientific mind when the discussion arose was this,--to ascertain whether an origin of vital activity could be observed in the midst of materials from which all germinal forms of life were certainly excluded.