which human reproduction and sex may be enveloped. 

 The human conditions are so interwoven with plant and 

 animal processes that the essential truths may be assimil- 

 ated incidentally to the school course in the life-sciences 

 and with the minimum of special instruction on the sub- 

 ject, which may easily become hurtful. 



The writer is convinced that there is much in the life- 

 sciences that may be made appealing to the general reader. 

 There is no field of science from which come more dis- 

 coveries of vital interest to human life and thought. No 

 modern progress has brought out more that is wonderful 

 and important than our advances in biology. Many of 

 these relate to reproduction and are touched upon in this 

 essay. 



It is a pleasure to acknowledge helpful criticisms and 

 suggestions from Mr. Maximilian Braam of Hughes High 

 School, Cincinnati; and from Dr. John G. Coulter, the 

 editor of the Series. Acknowledgment is also made of 

 the courtesy of the American Book Company in connec- 

 tion with use of the illustrations on pages 3, 12, 18, 26, 28, 

 30, 38, 39, 50, 12, 76, 102, and 103. 



T. W. GAI.I.OWAY. 



