Biological Papers. 147 



chemist so beautifully in the working out of his chemical reactions, 

 that many old-time college-made biologists very naturally turn to 

 these chemical and physical forces for the causes of vital phenom- 

 ena. Hence we have the germ-plasm theory of Weismann, the 

 laws of Mendel, and the attempts to find life in the crucible made 

 by Loeb and Schaefer. The chemical and physical forces can be 

 measured and expressed in terras of standard units, while life, a 

 variable, does not lend itself so readily to the mathematically 

 minded for expression. 



Chemists, physicists and astronomers know that chemism, cohe- 

 sion and adhesion, gravitation, all forms of radiant energy, and the 

 influence that controls the arrangement of molecules in crystals, 

 all obey laws that have not varied since the beginning of exact 

 human observation. Everyone,on the other hand, who has Aristotle's 

 entelechy within him, knows that life is a variable which may do 

 things differently to-morrow from what it does them to-day, in 

 both instances under precisely the same external conditions. 



This variability of life is worrying some of our modern biolo- 

 gists. Doctor Driesch, the great German vitalist, in a letter to 

 Lovejoy, of Johns Hopkins University, says, in an excerpt quoted 

 by Jennings, also of Johns Hopkins, and published in /Science for 

 October 4, 1912: "You are quite right in saying 'the biologist can 

 not from the kowledge of total physical configuration predict what 

 will happen even after he ha sobserved it.' This is, indeed, a con- 

 sequence of my vitalism, and I am glad that you appreciate it. I 

 reject absolute indeterminism, but accept experimental indeter- 

 minism." In their published correspondence in Science, continued 

 for two or three years, neither Jennings nor Lovejoy gives any 

 reasons for the fact that experiments on living organisms do give 

 results of high certainty. 



In several papers^ read before this Academy during the past eight 

 years I have reiterated the belief that the first activities of the first 

 cell of protoplasm on earth must have been performed consciously; 

 Uter, when these activities have been performed consciously many 

 times, they became in part habitual in the individual, and by con- 

 tined repetition through many generations they became largely 

 subconscious and instinctive tendencies in the species.^ We can 



1. Volume XIX. The Genesis and Development of Human Instincts. Volume XXI, Part I, 

 Anti(iuity of Man's Body-building- Instincts. Volume XXII, Weismann's Germ-plasm' Theory 

 Untenable. Volume XXIV. Origin and Development of Plant and Animal InstinctB. 



2. Dr. Charles S. Minot. of Harvard, in his presidential address before the American Abso- 

 ciation for the Advancement of Science, in 1902. at Pittsburjr. says, as a probable hypothesis, 

 ■ that conscious actions are primary: reflex or instinctive actions secondary; or, in other words', 

 thit for the benefit of the organism, conscious actions have b;en transformed into instincts and 

 reflexes." 



