Every symbiosis is in its degree underlain by hostility, and only by proper regulation and often elaborate adjustment, can the state of mutual benefit be maintained. Even in human affairs, partnerships for mutual benefit are not so easily kept up, in spite of men being endowed with intelligence and so being able to grasp the meaning of such a relation. But in lower organisms, there is no such comprehension to help keep the relationship going. Mutual partnerships are adaptations as blindly entered into and as unconsciously brought about as any others.