HEREDITY AND ENVIRONMENT 191 



prostate secretion tabloids curing chronic mastitis may be 

 mentioned (Lane). Since few biologists concern them- 

 selves as much as they should with physiology, and not at 

 all with pathology, which is just as necessary a part of 

 their proper apparatus, it may be pointed out that some 

 internal secretions have such observable effects in the 

 minutest proportions. That it becomes intelligible how the 

 minute parathyroids, four of which weigh two grains, 

 have such great physiological effects as to make certain 

 they are real determinants. According to Schafer, a strip 

 of intestinal muscle is affected by adrenalin in a solution 

 of i in 20,000,000 and a strip of coronary artery by i in 

 50,000,000. Pysemsky and Kravkov state that the effect 

 of one part in 250,000,000 could be detected when per- 

 fusing a rabbit's ear with Ringer's solution. Such results 

 may at least suggest that an almost infinitely small pro- 

 portion of an inorganic catalyst or organic secretion, 

 whether coming over in an egg or sperm cell, or taken in 

 later from the parental host, might be a determinant of 

 immense capacity. No doubt such ideas as these moved 

 Starling to the statement that " cell-division in the organism 

 might be spoken of as the evolution of a new kind of cell, 

 but that the change takes place within the development 

 of the multicellular parent, or host, instead of occupying 

 a long space of time and involving the destruction of 

 countless individuals as when a change of type occurs 

 gradually in a unicellular organism." Now, independent 

 of the fact that we have no evidence that a unicellular 

 organism may not change as quickly, or even more quickly, 

 when transferred to water with different saline constituents, 

 as an Alpine flower when transferred to the warm lowlands, 

 and even positive evidence that it can so change (J. Loeb), 

 it may be remarked that about seven months from im- 



