The results of early developmental and evolutionary biology texts can be best summarized, in my opinion, by
looking at the books'' introduction and preface to get a feel for the tone of the Author''s intention(s) for writing it. Further, one does well to next inspect the book for the Author''s novel
experiments; be there any, and ask, does the Author hold true to the introductions'' scope with its actual applications. Moreover, in early science and biology books there are often footnoted entries in the earlier text that lead to notes near the back of the book but earmark that are for the exact chapters. Scientific books have much more revealing bibliographical systems than other literary genres'' do. One must think of these things: The books'' Introduction, its experiments and its footnotes in Toto to be able to fairly get in league with the Author''s topic, or to fairly be able to objectively criticize it. We must give early science a fair shake in order to benefit from it or to be able to prevent its duplication so we can progress beyond with worthwhile new efforts. Please see for yourself if you think I give the 1877 science of K. Semper and his book, written more than 120 years ago, a fair shake now in 2007. Here''s a quote from the books'' preface. He said, all the hypotheses on
variability and heredity still await intrinsic explanation. Out of the various and heated opinions of his day he felt that the topic of ''variability'' was the easiest one to trace back to its efficient causes. The preface continues. I have endeavored to facilitate this task, so far as in me lies, by presenting a general view of those facts and hypotheses which bear upon the subject and are either of universal significance or, from my point of view, appear to offer favorable subjects for experimental treatment. This list, however, makes no pretension to completeness. If only it should give an impulse to research, on however small a scale, so long as it is systematically conducted and thoroughly carried through --if only it should contribute to extend my own convictions as to the uselessness of casual and disconnected observations, I shall have attained my end. Next, let us look at one of his experiments. This is a fitting topic because of the threat to amphibians we face today. Page 148, C. The effect of the different percentage of salt. If a frog absorbs more salt than it can bear, it will die, and its death will ensue all the sooner, the stronger the solution is in the first instance. A great number of frogs were placed in different vessels, each containing the same quantity of water with various, but known, amounts of salt in solution. By this I found that the frog commonly died, on an average, in about two hours and a half in a solution of five-per cent. of salt and not before more than twenty-four hours had elapsed in one and a half per cent. They all, without exception, endured a solution of one per cent. without sustaining any injury; that is to say, they lived as long in the very uncomfortable position (K Semper rigged up a way to keep the salty water from the frogs'' nose and mouth since absorption of salty water through the frogs'' skin was previously known and he was extending this prior knowledge towards his hypotheses) as other frogs which were fastened up in the same way in pure fresh water--namely from three to four days. The later fresh-water ones were His ''control specimens for this experiment. He also limited the number of variables to just one variable, the saltiness of the water to garner His results. This shows me he was doing very rigorous scientific method to try to define what He said in the preface, all the hypotheses on variability and heredity still await intrinsic explanation. Out of the various and heated opinions of his day he felt that the topic of ''variability'' was the easiest one to trace back to its efficient causes. Next let us check his expanded note for his numbet. It amazes me how with just a little set of initiatives enthusiastic people can scale the mount Everests of their aspirations. According to Bernard''s researches on the frog and Plateau''s on Crustacea, we might almost be tempted to suppose that all animals that migrate from the sea to rivers, and vice versa, the different degree of ‘saltness between their tissues and the surrounding water would be rapidly equalized by the osmotic action of the skin. In many creatures, as e.g., the Stickleback, this is no doubt the case.--Though as of 1877 no conclusive experiments had been made even on this fish. This regimen followed was just one such example of many in this book to further his own curiosity.