101 
ration. Strictly speaking, it is very seldom that two individuals exist which 
are exactly the same. So, a species is generally represented by an individual. 
That species which is generally used in systematic botany is, therefore, not 
a species in my sense, but a group of several individuals that bear a close 
resemblance. For convenience’ sake, the term species is in the present paper 
treated as a group like a genus or a family, only smaller than either of the two. 
4. WHAT THE RESEMBLANCE OF SPECIES DENOTES. 
Above, we have spoken of resemblance. But what is resemblance 
manifested in an individual or in a species? According to my opinion, the 
resemblance of individuals or species is not confined to cases of blood-relation- 
ship, but is manifested by the constitutional relationship. Now, what is meant 
by constitutional relationship ? 
In my former paper, I proposed the participation theory to explain the 
mutual relations of vegetable organs, individuals, or species. As the under- 
standing of the mutual relations is in this case a most important matter, I 
trust I may be pardoned if I repeat the theory in the following pages. 
5. THE PARTICIPATION THEORY”. 
The theory is in fact but one theory, yet for convenience’ sake I shall 
treat it as two, namely :—The theory of the mutual participation of the 
gene”, and the theory of the mutual sharing of the gene. Literally speaking, 
the word “ participation” seems to express a united action of genes to produce 
a certain result. Different genes participate in the effort to produce the 
resulting plant or plant organ. Different plants or plant organs on the other 
hand are found to share in the work of certain genes, or combination of genes ; 
or perhaps we may say that the word “ participation” points to the future, 
while the word “sharing” points to the work accomplished in the past. Thus, 
different genes participate in the work of producing a certain result, while 
different plants share with one another the work of certain genes. It must be 
1) In formulating this theory, I have been influenced by a suggestion from Trnpa1’s theory 
of mutual participation. ag 
2) As to what is the gene, readers are requested to refer to {two similes given on pp. 103 
and 104 of the present paper. 
