THE VITAL UNITS CALLED CELLS 203 



the cytologlst must be broadminded and friendly cooperation 

 is essential for his success. He is obhged to invoke assistance 

 on all sides. Through experience he usually acquires a pro- 

 found respect for the capabilities of these vital units and an 

 appreciation of the saying that "Nature moves in mysterious 

 ways her v^onders to perform." He is distrustful of the 

 simple cut and dried explanations sometimes offered by 

 his colleagues in other branches of science. It is a curious 

 paradox that those investigating vital phenomena, faced 

 as they always are by the unknown and unpredictable, 

 are much less ready to accept bhndly the existence of super- 

 natural deities or controlhng powers than are the astrono- 

 mers, physicists and mathematicians. When committees 

 are appointed to report on the relation of science and reli- 

 gion it is almost invariably workers in the exact sciences 

 who take the lead in assuring the laity that the two Hnes 

 of thought and action are fully compatible and reconcilable. 



For those who would understand, even in a halting way, 

 what hfe is, enough has perhaps been said to indicate the 

 interest which attaches to these elementary vital units 

 which are the highly adaptable building stones of the bodies 

 of all plants and animals. To the practical minded it may 

 be worth while to cite a few examples of how profoundly 

 the study of cytology has influenced human welfare. 



Of all the cells of the body the most easily examined are 

 those of the blood. Reference was made at the beginning 

 of this chapter to the white blood cells, or leucocytes. 

 A few minutes devoted to their study is often sufficient to 

 return a definite verdict as to whether an operation for 

 appendicitis should be undertaken. Similarly observation 

 of the red blood cells gives information which helps to tell 

 whether a patient is suffering from a simple secondary 

 anemia or from the dreaded disease known as pernicious 

 anemia, which latter is now happily greatly improved by 

 the administration of liver extract. When a tumor is dis- 

 covered and the surgeon while operating comes to suspect 

 that it may be a cancer, all he has to do is to arrange for 

 the cytological examination of a small fragment. In a few 

 minutes, while the patient remains under anesthesia, he 

 is told with considerable accuracy, from the appearance 



