Precaution Quotes (5 quotes)
Astonishing how great the precautions that are needed in these delicate experiments. Patience. Patience.
It was on the 25th November 1740 that I cut the first polyp. I put the two parts in a flat glass, which only contained water to the height of four to five lignes. It was thus easy for me to observe these portions of the polyp with a fairly powerful lens.
I shall indicate farther on the precautions I took in making my experiments on these cut polyps and the technique I adopted to cut them. It will suffice to say here that I cut the polyp concerned transversely, a little nearer the anterior than the posterior end. The first part was thus a little shorter than the second.
The instant that I cut the polyp, the two parts contracted so that at first they only appeared like two little grains of green matter at the bottom of the glass in which I put them—for green, as I have already said, is the colour of the first polyps that I possessed. The two parts expanded on the same day on which I separated them. They were very easy to distinguish from one another. The first had its anterior end adorned with the fine threads that serve the polyp as legs and arms, which the second had none.
The extensions of the first part was not the only sign of life that it gave on the same day that it was separated from the other. I saw it move its arms; and the next day, the first time I came to observe it, I found that it had changed its position; and shortly afterwards I saw it take a step. The second part was extended as on the previous day and in the same place. I shook the glass a little to see if it were still alive. This movement made it contract, from which I judged that it was alive. Shortly afterwards it extended again. On the following days I saw the same thing.
I shall indicate farther on the precautions I took in making my experiments on these cut polyps and the technique I adopted to cut them. It will suffice to say here that I cut the polyp concerned transversely, a little nearer the anterior than the posterior end. The first part was thus a little shorter than the second.
The instant that I cut the polyp, the two parts contracted so that at first they only appeared like two little grains of green matter at the bottom of the glass in which I put them—for green, as I have already said, is the colour of the first polyps that I possessed. The two parts expanded on the same day on which I separated them. They were very easy to distinguish from one another. The first had its anterior end adorned with the fine threads that serve the polyp as legs and arms, which the second had none.
The extensions of the first part was not the only sign of life that it gave on the same day that it was separated from the other. I saw it move its arms; and the next day, the first time I came to observe it, I found that it had changed its position; and shortly afterwards I saw it take a step. The second part was extended as on the previous day and in the same place. I shook the glass a little to see if it were still alive. This movement made it contract, from which I judged that it was alive. Shortly afterwards it extended again. On the following days I saw the same thing.
My belief (is) that one should take a minimum of care and preparation over first experiments. If they are unsuccessful one is not then discouraged since many possible reasons for failure can be thought of, and improvements can be made. Much can often be learned by the repetition under different conditions, even if the desired result is not obtained. If every conceivable precaution is taken at first, one is often too discouraged to proceed at all.
To save every cog and wheel is the first precaution of intelligent tinkering.
When one studies strongly radioactive substances special precautions must be taken if one wishes to be able to take delicate measurements. The various objects used in a chemical laboratory and those used in a chemical laboratory, and those which serve for experiments in physics, become radioactive in a short time and act upon photographic plates through black paper. Dust, the air of the room, and one’s clothes all become radioactive.