20 SURVEY OF THE REPRODUCTIVE PROCESS 



and as fully as is consistent with the brief limits to which 

 I feel that I should confine myself in such a summary. 



As Reproduction, like other functions, is performed in a 

 less complex way in the more rudimentary forms of organi- 

 zation, I propose proceeding from the lower to the higher 

 species, and for similar reasons, I commence with the Vege- 

 table kingdom. 



2. A few remarks may be made, by way of introduc- 

 tion, concerning the general characters of the process in 

 this division of organized nature. 



Indications of sexual relations in the function of repro- 

 duction, have now been so generally ascertained, as to make 

 it highly probable that they are always present. Three 

 principal modifications have been recognized in cases where 

 their existence has been positively ascertained. 



The most rudimentary manifestation of sexual action 

 occurs in the conjugation of the lower Algae. In these 

 simple forms of living matter there is at first no differentia- 

 tion of organs for the work of reproduction, more than for 

 any other vital function. The plant consists simply of a 

 repetition of cells, which whether isolated or aggregated 

 into fronds, (tumid, membranous, or filamentous) are in- 

 distinguishable from each other, being all nucleated and 

 filled with a green granular mass, termed endochrome. In 

 the farther development of the cells, we find that in those 

 which are to take part in the reproductive process, the en- 

 dochrome becomes condensed into a spheroidal mass ; after 

 this, a communication is established between two neigh- 

 bouring cells by a perforation of their walls, and a fusion 

 of their contents takes place, resulting in the formation of 

 an embryonic corpuscule, which eventually becomes a true 

 cell, by the formation of a proper wall on its exterior. 

 Along with a general sameness in the essential features of 

 this process, in all the simpler Algae or Protophyta, there are 

 certain specific differences, mainly dependent on variations 



