INHERITANCE 105 



mind when dealing with Inheritance. Let us now 

 consider in what way the problem may best be 

 attacked. 



Of Theories of Inheritance there are two which 

 have attracted special attention, and which demand 

 careful consideration. These are, first, Mr. Darwin's 

 " Provisional Hypothesis of Pangenesis ; " and 

 secondly, the view more recently advanced by 

 Professor Weismann, of Freiburg. 



Mr. Darwin's Theory is stated by himself as 

 follows : " It is universally admitted that the cells or 

 units of the body increase by self-division or pro- 

 liferation, retaining the same nature, and that they 

 ultimately become converted into the various tis- 

 sues and substances of the body. But besides 

 this means of increase, I assume that the units 

 throw off minute granules, which are dispersed 

 throughout the whole system ; that these when 

 supplied with proper nutriment, multiply by self- 

 division, and are ultimately developed into units 

 like those from which they were originally derived. 

 These granules may be called gemmules. They 

 are collected from all parts of the system to consti- 

 tute the sexual elements, and their development in 

 the next generation forms a new being ; but they 

 are likewise capable of transmission in a dormant 

 state to future generations, and may then be 

 developed. Their development depends on their 

 union with other partially developed or nascent 

 cells, which precede them in the regular course 

 of growth. Why I use the term union, will be 

 seen when we discuss the direct action of pollen 



