But some of the materialists claim that what we call "vital units," or invisible, indestructible germs,[33] are at best only "physical relations;" that they have nothing more than a hypothetical existence, without any independent recognizable quality justifying our conclusions respecting them. But may not this identical language be retortively suggested in the case of their "correlates of force?" What more than a hypothetical existence have they? Certainly their enthusiasm to get rid of all vital conditions or manifestations, is quite as marked a feature in their speculations respecting life as any enthusiasm we have shown in the verification of vital phenomena, on the established law of cause and effect. They insist upon this law in the case of statical aggregates, and even assign absolute identity of attributes; but when it comes to dynamical aggregates, they fall back on partial identity only, and deny the presence of the law altogether. Nor are they any more felicitous in their treatment of other points in controversy. In speaking of his "plastide particles," Professor Bastian, the most defiant challenger of vitalistic propositions now living, says: "Certain of these particles, through default of _necessary conditions,_ never actually develop into higher modes of being." Here he makes the absence of "necessary conditions" the cause of non-development, while he stoutly denies that the presence of such "conditions" give rise to the development of a pre-existing vital unit. And yet, strange to say, he speaks of the elemental origin of "living matter" as "having probably taken place on the surface of our globe since the far-remote period when such matter was first engendered." But how his "sum-total of external conditions," acting upon _dead_ matter, can "engender" _living_ matter, is one of those "related heterogenetic phenomena" which he does not condescend to explain. It is by this sort of scientific verbiage that he gets rid of the pre-existing vital principle, or germinal principle of life, which the biblical genesis declares to be in the earth itself.