166 UNIVERSITY OF MISSOURI BULLETIN 



able subject for intercollegiate debates, was settled for all time 

 by experiments and observations. 



Nearly every science dates a period of rapid advance 

 from the invention of some piece of apparatus or instrument 

 of precision, witness the balance in chemistry, the telescope 

 in astronomy, the thermometer in medicine. A new epoch in 

 botany was ushered in by the invention of the compound 

 microscope. Not only was a whole new world opened up for 

 investigation, and the study of non-seed-bearing plants as 

 well as of seed-bearing plants made possible, but a whole 

 series of hitherto undreamed of problems arose out of the 

 newly discovered facts. The formerly impossible, but abso- 

 lutely necessary, task of following the complete history of 

 development of a plant now became possible. And, more 

 important than all else, "Investigation by means of the micro- 

 scope enforces on the observer the very highest strain of at- 

 tention and its concentration on a definite object, while at the 

 same time a definite question to be decided by the observa- 

 tion has always to be kept before the mind ; there are sources 

 of error on all sides to be avoided, and possible deceptions 

 to be taken into consideration ; thus serious attention to micro- 

 scopy was one of the causes which introduced the best ob- 

 servers to the practice of inductive inquiry."* 



To make satisfactory microscopical observations re- 

 quires special preparation of the tissues. Among other 

 things, they must be examined in extremely thin sections 

 because they are observed not, as in naked eye study, by re- 

 flected light, but by transmitted light. Often, also, it is es- 

 sential to have these thin sections of uniform thickness and 

 arranged in serial order. To realize these conditions was 

 difficult and tedius when all the sections had to be cut with 

 a razor by hand. The invention and perfection of the micro- 



*Sachs, J. History of Botany. Eng. Trans, by Garnsey and 

 Balfour. Oxford, 1906. p. 182. 



