92 
EDWARD TYSON REICHERT 
substances, the differences are owing to variations in the Hnkages of 
the components, which differences are expressed by structural formulae 
that set forth the linkages in the two dimensions of space; and that 
when substances have the same molecular and structural formulae 
but differ in their properties, the differences are due to variations in 
the arrangements of the components in three dimensions of space, 
that is, in the configurations of the molecules, which differences are 
expressed by space formulae. Bodies belonging to the last group are 
known as stereoisomers or corresponding substances, that is, each 
kind of substance may exist in a number of forms, all of which forms 
have the same molecular formula, the same structural formula, and 
the same fundamental properties in common, but each in accordance 
with variations in intramolecular configuration has certain indi- 
vidualities which distinguish it from the others. 
There are many known substances that exist in stereoisomeric 
forms, and it has been found that the number of possible forms of each 
substance is dependent upon the possible number of variations of 
the arrangements of the molecular components in the three dimensions 
of space, or, in other words, of variations of molecular configuration, 
the possible number in case of each substance being capable of mathe- 
matical determination. Thus, we find that serum albumin may exist 
in as many as a thousand million forms. Haemoglobin, the red 
coloring matter of vertebrate blood, is a far more complex carbon 
compound than serum albumin, and theoretically may exist in forms 
whose number is beyond human conception, running into millions of 
millions. The same is true of starch. 
Elsewhere^ have been set forthwith sufficient fullness the hypotheses 
and theories that underlie an elaborate series of researches which 
have as their primary object an investigation of corresponding sub- 
stances obtained from various forms of plant and animal life in relation 
to taxonomy, sports, mutations, reversions, heredity in general, tumor 
formation, etc., and nothing more seems necessary in the present 
address than to state that these researches have as their essential basis 
the conception that in different organisms the corresponding complex 
organic substances which constitute the supreme structural com- 
ponents of protoplasm and the major synthetic products of proto- 
plasmic activity are so different as to impart specific peculiarities to 
the organisms in which they are formed, to be as distinctive of the 
1 Publications ii6 and 173 and the Year-Books 9 to 13 of the Carnegie Institu- 
tion of Washington. 
