314 



SCIENCE 



[N. S. Vol. LI. No. 1317 



Are we to forget that we now have micro- 

 scopes, in order to let history imify our sub- 

 ject for us? History may explain a good 

 many discrepancies, especially in earlier biol- 

 ogy, but it does not unify anything. History 

 unifies only subjects that are essentially his- 

 torical in their nature, like political develop- 

 ment, or philology. I do not mean that his- 

 tory is uninteresting or unimportant, for it is 

 neither; but it unifies only the history, not 

 the content, of biology. Only the facts of a 

 science can unify the science itself. 



Unity can be acquired only by arranging 

 subjects, placing the simple first, and laying 

 thereby a foundation for related subjects that 

 are more complex. Each subject should lead 

 to another, and rest upon those that precede. 

 Such unity a course based on the dissection 

 of types can have only in small degree. 

 Otherwise one teacher could not begin with 

 Protozoa, another with vertebrates, or another 

 with Arthropoda which are followed by Pro- 

 tozoa, leaving the vertebrates to the last. 

 Did types insure unity, we would not have 

 that interesting chapter on " animals of un- 

 certain afEnities" squarely in the middle of 

 the course, l^ematodes do not lead naturally 

 to the Bryozoa, nor do the annelids obviously 

 follow the echinoderms. There is no mani- 

 fest necessity for having the moUusks precede 

 the arthropods. The teacher of the type 

 course may claim unity for his course, on the 

 ground that he goes from the simple to the 

 complex. A grindstone, a bicycle, a type- 

 writer and a calculating-machine may be 

 arranged in order of complexity, but the 

 unity permeating the series still not be very 

 obvious. 



Homology, on the contrary, does lead to 

 taxonomy, taxonomy and ecology to distri- 

 bution, distribution in space to distribution 

 in time. Cell division leads to cell aggrega- 

 tion, and reproduction to embryology. The 

 connections stated are not merely obvious, 

 they are necessary. 



The study of topics entails certain difficul- 

 ties, one of them being the larger amount of 

 diverse material required in the laboratory. 

 Some may think that this use of many differ- 



ent animals is confusing, rather than unify- 

 ing. Our experience indicates that such is 

 not the case. Using many animals to demon- 

 strate the truth of the cell doctrine is not 

 more confusing than the study of profit and 

 loss in arithmetic by problems involving 

 vinegar, woolen goods, automobiles, and 

 ostrich feathers. What woiild be thought of 

 an arithmetic that employed problems re- 

 lating to vinegar for addition, division, profit 

 and loss, compound interest and cube root, 

 before woolen goods were used to illustrate 

 the same operations? Or what of a school 

 system in which vinegar was studied chem- 

 ically, biologically, and industrially before 

 woolen goods were studied from the same 

 points of view? Those would be type studies, 

 type aritlmietics, type school systems. 



In only one other science, so far as I am 

 aware, do teachers as consistently use the type 

 method as we have done. Whether another 

 method would do as well in that subject I am 

 not qualified to say. Biology is, then, one of 

 the few sciences which have allowed their 

 wealth of material to obscure their subject 

 matter. 



How do the students react to the treatment 

 I have described? Perhaps, although the 

 course has been given seven times, we have 

 not been using the new method long enough 

 to speak authoritatively; but some things 

 seem to be observable. I have seldom heard 

 students ask that question formerly not in- 

 frequently heard, not only in our own lab- 

 oratories but in those of other institutions, 

 " How much of all this are we expected to 

 remember?" Students now recognize for 

 themselves that the things which they study 

 are important, for they draw conclusions from 

 them. They have perhaps been quicker than 

 teachers to see the advantages of the new 

 method. Verily, these things were hid from 

 the wise and prudent, and were revealed unto 



If culture be measured by the number of 

 ways one has of entertaining himself, cer- 

 tainly the knowledge of biological principles 

 far outweighs from the cultural standpoint 



