Lessons and experiments on scientific hygiene and temperance for elementary schoolchildren / by Helen Coomber.

Coomber, Helen.

Date:: 1914

Credit: Lessons and experiments on scientific hygiene and temperance for elementary schoolchildren / by Helen Coomber. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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$this lesson will end hero. If imiwssible to arrange the tadpole under a microscope, put up diagram and discuss.) If you could see the blood in the tiniest branches of one of your arteries you woirld see something lilcc this. [Names not to be written up foi' tlic clnldren.] C are cells containing protoplasm. Tliey form the greater part of the tail, and running among them are the branching tubes through which the blood rushes, but it would not look just a red liquid, you would see a number of faintly reddish, oval-shaped bodies (like R) rushing along in a colourless liquid, sometimes squeezing round corners into the narrower tubes. They are protoplasm or living substance, separate cells just as the yeast cell was, and are called red corpuscles {cle, little; c^9. icicle). Corpus, jou know, is corpse—body, so words mean red little bodies. They are little indeed. Here I have a shapes of a single white corpuscle at different , ,. 1 1 j_ 1 moments. gelatme model to show ?! • 1 r\ ^ Fig. 60. their shape. Uval, hollow one side. Model is an inch long. If I could put 3000 of the red corpuscles side by side they would just reach across it, so they are very small but there are as many as 5 millions of them in a drop of blood the size of a pin's head. Now why do you think blood is an aU-red liquid Corpuscles are so closely packed that you can't possibly see the spaces in between when blood is shed, so you think it is red all through. If you look very careftdly at the vessels you can sometimes see also some quite colourless round little bodies. What do you think they might be called ?— White corpuscles. They too are life substance, and they can change their shape, sometimes pushing out at one side, sometimes at another. How many have I put ui the diagram ?—Only three. They are much fewer than the red corpuscles—1 white, 500 red. Of course that means millions in the whole body. I,$