VALUE OF CULTURAL CHARACTERS. ibl 



layers of the agar, /. e., to rapid loss of water, and experiments have shown this to 

 be the case. Two sets of Petri-dish poured plates were made, inoculating from the 

 same culture. One set was exposed in the open thermostat at 37" C, and these 

 developed round colonies, similar to those shown in fig. 144. The other set was 

 inclosed in the same thermostat, but inside of a closed glass vessel containing water. 

 The colonies on these grew in radiating form, the same as in a third set of plates 

 exposed at 30" C. This does not account, howe\-er, for the appearance of circular 

 colonies at low temperatures. After twelve days' exposure in an ice-box the writer 

 obtained the same result as Townsend ; the colonies were not radiate, but looked 

 like those shown in fig. 144. 



Undergraduate Work. 



As a rule, the results of this kind of investigation are to be distrusted. The 

 fresh ambition of students and their delightful eagerness to take up hard problems 

 are sources of great pleasure to even' good teacher. At the same time such students 

 must be held back rather than urged on, since for the most part tliev are still unfitted 

 to do independent work, especially that which involves the drawing of general 

 conclusions from a variety of experiments. The ordinary training of l:)otanical and 

 zoological laboratories will not fit the student for specialization in patholog;}- and 

 bacteriology. Skill in this sort of work must be oDtained from consorting with 

 the pi'ofessional pathologist and bacteriologist. In general, at the present time 

 a well-equipped modern laboratory devoted to animal pathology is a nuich better 

 place for the plant bacteriologist to learn methods than even our best-equipped 

 botanical laboratories. One of two alternatives is open to the ambitious student. 

 Either he must submit to a long and rigorous course of elementary stud\- in a 

 bacteriological laborator)', under a competent and critical teacher, or else he must 

 be content to pick up the general principles of the science out of books and 

 journals, with much blundering and stumbling in the first }'ears of his study. 

 During this nurser\- period, if he is jealous of his own reputation, he will not 

 publish much. Aly experience has led me to discount very liberally the conclusions 

 of student investigators, and I consider those students ver}- unfortunate whose 

 teachers urge them into precocious publication. In many cases nothing could be 

 more damaging to their own reputation as scientific inquirers, or more injurious to the 

 progress of science. Bad papers also react upon the teachers of such students, who 

 can not by an}- shift e\'ade responsibility. My advice to teachers is to discourage 

 all students who do not show marked aptitude, and to give to those who do show 

 signal ability the best possible training in iiietlwds of work^ but to discourage 

 them from undertaking difficult pieces of original investigation. The only alterna- 

 tive is for the teacher to follow their work step by step and assume joint responsi- 

 bility for it in the end. Even this latter course is sometimes risky, as the histor}' 

 of science shows ver)' conclusively. 



After a year or two of careful work on methods, under the watchful supervision 

 of a good teacher, the bright student will have learned how to avoid many of the 

 pitfalls which beset his way, and, if he has acquired a proper training in other 

 directions, such as general botany, modern physics, chemistr\', the modern languages, 



