EXPERIMENTAL EQUIPMENT AND PROCEDURES 



in hypertonic salt solutions or dilute potassium permanganate, either of which appears 

 to be bacteriocidal. Generally such treatment is unnecessary, and should be avoided, 

 if other precautions are taken. Also, if the embryos are kept at the lowest but toler- 

 able temperatures, and the dishes are covered, there is less likelihood of infections 

 killing them. (See special directions for chick and mouse embryos) 



The sooner the student insures personal and operative "biological cleanliness." the sooner 

 will he obtain reproducible experimental data, and enjoy the experiences of experimental 

 embryology. It is a complete waste of time and talent to allow contamination to invali- 

 date experimental data. 



THE EXPERIMENTAL PROGRAM 



Every experimental program is built upon a foundation of facts, or theories, well sup- 

 ported by demonstrated facts, and must follow a very definite course if the results are to 

 be reproducible and acceptable. It should help the beginning investigator to outline such 

 a research protocol in order to instill in him the habit of rigid and coniplete planning. 

 This does not imply that anyone can forsee the results of an experiment. Indeed, the 

 research worker must at all times avoid the pitfall of prejudicial planning, of a program 

 designed to prove rather than investigate some pre -conceived concept. A research 

 worker, true to his opportunities, will be entirely open-minded to the consequences of 

 his research. His planning should be designed to investigate an unexplored area, and his 

 reward will be discovery, often in unpredictable directions. 



The unplanned, or the unintelligently-planned research program, usually results in 

 wasted materials, effort, and talent. The uninitiated investigator too often finds, at the 

 conclusion of his program, that he has omitted some vital procedure or has tragically 

 by-passed some fruitful corollary. Thus, as experience is accumulated, the initial re- 

 search program will become much more specific, but as the research is in progress the 

 ramifications become more varied. With experience, the results of genuine experimen- 

 tation are inore subject to prediction and more apt to open up new and wider vistas of 

 challenge. The research worker does not, therefore, put his program into a machine 

 and await the end results but rather designs his program on the basis of facts and theo- 

 ries, and is ever alert during the investigation for new challenges for an inquiring mind. 

 The program should never be final, unalterable, but pragmatic and subject to change as 

 new facts are revealed. 



In light of the above, an outline is suggested which might be useful not only in planning 

 an experiment but in reporting it for publication in a scientific journal. Again, this is 

 only suggestive, but is offered as a protocol for complete research thinking and plan- 

 ning. 



THE RESEARCH PROTOCOL 



PURPOSE: Here the major purpose of the investigation should be succinctly stated. For 

 example, it could be: "To determine the effect of temperature on the growth rate of 

 the tadpole of the frog, Rana pipiens. " 



Such a statement gives immediately the one major variable, temperature and 

 the test object or situation, growth rate, and, most important, the form used, Rana 

 pipiens tadpoles. There can be no. doubt by anyone that if the purpose is achieved, 

 there will be established some correlation between temperature and growth rate. 



But, one cannot always anticipate that results will be positive so that the purpose 

 might be stated: "To investigate the possible relation between temperature and 



