It is important to note that Jordan's publications regarding eugenics do not have a very scientific basis, despite his extensive training in biology and zoology.  These works seek to persuade and educate the general public through common knowledge stories of history and selected narratives transformed into parables. "In beginning this discussion I must bring forward certain fragments of history, stories told because they are true, and one parable not true, but told for the lesson it teaches" (#1 p. 13)

The Human Harvest

Before the Table of Contents, Jordan includes a Prefatory Note regarding the topic at hand: "How long will the Republic endure? [...]  Our Republic shall endure so long as the human harvest is good, so long as the movement of history, the progress of science and industry, leaves for the future the best and not the worst of each generation"   This sets the tone for the series of narratives featured in the text.

The author begins with a discussion of horse breeding as a parable for mankind.  "Once there was a man, strong, wealthy, and patient, who dreamed of a finer type of horse than had ever yet existed."
He then points out the way traits are transferred through the generations and influenced by four factors: segregation, variation, heredity, and selection.  He then personifies each of these factors in the story of how the perfect horse is created. "And here came the need of the second genius, who is called Heredity.  With the crossing of the racer with the thoroughbred, all qualities of both were blended in the progeny." It is important to note that even though Jordan was very aware of the influence of the environment on an individual's traits, he still claims here that Heredity captures "all qualities" to be passed to the subsequent generations.  He then follows with another story of horses, one which the weak and sluggish horses remained in the stall to procreate while the strong fleet worked hard on the racetrack and in the fields.  The four "genii" of segregation, variation, heredity, and selection were forced to create generations who were spiraling downward simply because "the horse harvest was bad."
(#1 p. 14-21)

Jordan now turns toward history and the story of Rome.  He attributes the fall of Rome to the degeneration of its people: "Vir gave place to homo," real men to simply human beings.  In this section he continues the personification of the "four genii" but also adds the Spirit of Freedom and the Spirit of Domination.  During the early days of Rome's empire, The Spirit of Freedom held all control.  However as the empire expanded, the Spirit of Domination soon overcame Freedom and brought with it aggression, struggle, and war.  The subsequent invasions and endless wars caused a "reversal of selection" and and ultimate destruction of the empire.  During this section, Jordan also makes strong remarks regarding the dysgenic nature of war. "Whatever the remote and ultimate cause may have been, the immediate cause to which the fall of the empire can be traced is a physical, not moral decay."  (#1 p. 22-35.)

The essay ends with a warning to its readers.  "Does history ever repeat itself?  It always does if it is true history.  If it does not we are dealing not with history but with mere succession of incidents.  Life causes produce effects, just as often as man may choose to test them.  Whenever men use a nation for the test, poor seed yields a poor fruitage.  Where the weakling and the coward survives in human history, there "the human harvest is bad" and it can never be otherwise." (#1 p. 35.)  Jordan seeks to educate his readers in order to prevent this atrocity from affecting a whole nation ever again.

The Blood of the Nation

"In this paper I shall set forth two propositions: the one self-evident; the other not apparent at first sight, but equally demonstrable.  The blood of the nation determines its history.  This is the first proposition.  The second is, The history of a nation determines its blood." (#2 p. 7)

This strong statement opens Jordan's second publication regarding eugenics.  In many ways it is a continuation of The Human Harvest, published three years later and actually attached to the first work in later editions.  While Jordan repeatedly uses "blood" to designate the vehicle of heredity because "it serves our purposes", but he notes in the first section that this is not entirely the case.  This is firm rejection of Lamarckian theory by recognizing that environmental effects of the "blood" are not necessarily transferred to subsequent generations.

Jordan continues with a description of race degeneration when the strongest and fairest cows are not allowed to parent the subsequent herds.  He remarks "On the other hand, if we sell or destroy the rough, lean, or feeble calves, we shall have a herd descended from the best."  (#2 p. 12)  If this is taken as a parable for mankind, Jordan can be assumed to be anti-immigration and pro-sterilization.  However, based on his other works and remarks, this is not actually the case.  (See Later Life and Immigration.)  The essay continues with elaborate descriptions of the feudal system in France and the monarchy in England, especially in comparison to a hive of bees (no doubt due to Jordan's strong background in zoology.)