Spencer gives striking structural analogies between society and organism. He says, society, too, has three systems corresponding to the (a) sustaining system, (b) the distributary system, and (c) the regulating system in an organism.

The sustaining system in an organism consists of mouth, gullet, stomach and intestines. It is by means of this system that food is digested and the whole organic machine is sustained. Society has its own sustaining system which refers to the productive system comprising the manufacturing districts and agricultural areas. The workers, i.e., the men who farm the soil, work the mines and factories and workshops are the alimentary organs of a society.

The distributors system in an organism consists of the blood vessels, heart, arteries and veins and they carry blood to all parts of the body. Means of communication and transport and along with them the wholesalers, retailers, bankers, railway and steamship men and others may correspond to the distributor or vascular system of an organism. Society’s Cells are individuals only. And what the arteries and veins mean to the human body, roads, railways, post and telegraph services, institutions and associations, mean to society.

Finally, the regulating system is the nerve-motor mechanism which regulates the whole body. Government in society regulates and controls the activities of the individuals. The professional men-doctors, lawyers, engineers, rulers, priests, the thinkers, in short, perform the functions of the brain and the nervous system. Further, as Spencer opined society also passes through the organic processes of birth, youth, maturity, old age and death.

In a nutshell, Spencer indicates that society resembles an organism in the following important respects.

1. Society like organism grows or develops gradually. The human organism goes through the laws of development, maturation and decline. Similarly society also passes through some taws such as the laws of birth, growth and change or decay.
2. Both society and organism begin germs.
3. Society and organism both exhibit differential structure functions.
4. Both society and organism are composed of units. Society is composed of the individuals and thus, individuals are considered as the units of society. Similarly, organism is also composed of different organs such as eyes, ears, hands, legs, head etc., and these are regarded as the units of an organism.
5. In both society and organism there exists close integration or interdependence of parts. Just as the different parts of the organism are mutually interdependence and on the whole, also the individuals in a dependant are mutually interdependent like the cells in an organism dependent in the whole.