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Page:Popular Science Monthly Volume 90.djvu/400

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384

��Popular Science Monthly

��Why Does the Heart Stop Beating at Death?

THE question, "Why does a man or an animal die?" has been answered, "Because the heart stops beating." But any hunter or fisherman who has dressed his own catch can testify to the fact that the heart does not stop beating at the moment of the animal's death. Often it will continue to pulsate rythmically for several minutes after it has been removed from the carcass. The most recent answer to the "Why?" of this is that the heart muscles themselves possess the inherent quality of contraction and will contract, or beat, just as soon as or as long as the conditions of environment are right. That is their business and they can no more refrain from doing it under the right con- ditions - than a rose could help giving out its fragance.

In recent experiments it has been found that heat is the principal element. necessary to the development of heart muscles and their subsequent action. It is possible tO' grow the heart muscles of a warm-blooded animal in an incubator. During this growth a single muscle cell has been ob- served to develop and wander away from the mother cell and begin to beat of its own accord. Again, several individual cells may attach themselves to each other in a colony and beat rythmically together as long as the environment is favorable.

��But let the temperature of the incubator be materially reduced and the action of the heart muscles becomes sluggish. Re- duce the temperature still further and gradually the rythmic action ceases al- together. The cells cease to perform their natural function because their environment is no longer right. In other words, they die because they are cold. According to this theory, the heart muscles, could live on independently of a body, if kept at the proper temperature for their best^develop- ment.

��A Land Ride for Whales in South Africa

AHUGE motor-truck equipped with flanged wheels for use on a standard- gage railroad has come to the rescue of a whaling company in South Africa and has solved its transportation problem. The whales are carried by truck from the shore and are transported to the factory to be treated for the extraction of oil and other products.

The whales are hoisted on the truck by means of derricks and when once in place on the truck body they are securely lashed by chains. The truck is sixty-five feet long. It has a capacity of one hundred and sixty thousand pounds. The six-wheeled sup- ports for the truck body keep the axle loads down to the required limits and insure the necessary flexibility over the railroad line.

���Transporting whales in South' Africa by means of a special motor-truck railroad car. Whales weighing as much as eighty tons can be transported in this manner from the shore to the

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