RESEARCH IN BIOLOGY 15 



Ideally, the experimenter hopes that the experimental treatment will 

 not influence the results, but this desire can never be realized. The best 

 that can be hoped for is to reduce the interference to a minimum. Obvi- 

 ously, if the techniques of the experiment influence the organism, con- 

 trolled experiments are essential before any conclusions can be drawn. 



The blologisfs assumptions 



Although some of them have been mentioned previously, it is probably 

 wise to explain the assumptions which, in addition to the general assump- 

 tions of science, are made by the biologist. 



(1) Living organisms obey the laws of physics and chemistry. This 

 item has already been discussed. The only step necessary to prevent the 

 invalidation of this assumption is to incorporate any inconsistent dis- 

 coveries in biology into the physical laws. 



(2) The whole living organism is nothing more than the sum of its 

 parts. This assumption is made with two diff^erent meanings. The first 

 meaning is an outgrowth of the previous assumption, indicating that 

 there is nothing about the life of the whole organism that cannot be 

 explained by the physics and chemistry of the individual activities. The 

 second meaning refers to the use in experiments of parts of organisms, 

 rather than whole organisms. Much of our current knowledge of cellular 

 physiology has been derived from studies with isolated cells, or even 

 with parts of cells like mitochondria, ribosomes, chloroplasts, and puri- 

 fied enzymes. The assumption is made that these parts respond the same 

 when isolated as when contained in the intact organism and that, once 

 the activities of all the isolated parts are understood, it will be possible to 

 integrate these understandings into an explanation of the life of the 

 intact cell. 



(3) The experimental treatment does not aff^ect the process being 

 investigated too much. This is the hardest of the assumptions to make 

 with any confidence. The biologist often must use considerable ingenuity 

 in the planning of experiments in order to feel confident in interpreting 

 the results. 



(4) Related organisms, or parts thereof, will have identical or similar 

 behavior under the same circumstances. This assumption is not always 

 needed but is especially useful when dealing with human problems. 

 Most experiments with human beings would be both unethical and 

 immoral, and we must depend upon information from other animals. 



