Page:Popular Science Monthly Volume 19.djvu/882

862 paralyzed after he reached home, so that he considered his life in danger. All the precautions suggested by experience and careful observation were adopted for the protection of the men, and the cases of affection were watched as they occurred. In all, with six hundred men employed, one hundred and nineteen cases important enough to need medical treatment were reported at both piers, fourteen of which cases died and two were crippled. Post-mortem examinations were held in the cases of eight. Various theories have been proposed to account for the affection. Dr. Clark, of the City Hospital at St. Louis, believed that the congestion observed was caused by the forcing of the blood in upon the interior organs of the body in consequence of the increased atmospheric pressure. Another physician thought the men were poisoned by carbonic acid which had been abnormally retained within the system while in the air-chamber, but which was set free as soon as the pressure was removed. Dr. Jaminet thought the cases were due to physical exhaustion caused by breathing an atmosphere of quadruple strength, and supported his view by reference to the facts, all of which seemed to agree with it. Professor Woodward does not contradict his theory, but suggests in addition that the vital energies of the men taken sick were to a great extent paralyzed by loss of heat, which was due—1. To the expansion of the air in the lock while coming out; 2. To the expansion of the free gases and vapors within the body when relieved of the abnormal pressure; 3. To the liberation of the gases held in solution by the liquids of the body; 4. To the severe physical effort of climbing the stairs. The loss of heat taking place under diminution of pressure from four atmospheres to one would, if no heat were received from surrounding objects, be enough to reduce the temperature from 70° above to 106° below zero. Taking into consideration the condition of men who have been working hard, especially if they have not been well clothed and fed, it is not strange that they did, but rather that more of them did not, succumb under the combined effects of these four agencies. Dr. Jaminet gives an implied confirmation of these views by remarking in his pamphlet that "the paresis is but the result of reflex action caused by the spontaneous refrigeration of the whole system, but principally of all the abdominal organs." It is also worthy of remark that none of the men were ever attacked on entering the caisson, and none were ever sick while in the air-chamber, no matter how long the watch, but the attack always came on within half an hour after leaving the air-lock, or at the time. On the basis of this theory Professor Woodward establishes a system of rules for the management of men at work in compressed air, embodying the principles that only sound men should be employed, that they should be guarded against exhaustion, that they should not be exposed with unnecessary suddenness to the change from a compressed to the normal atmosphere; and that such a supply of heat should be given every man that he could lose a large amount and still have plenty left.

The Study of Anthropology.—M. P. Topinard classifies the anthropological sciences in three divisions. The first division, anthropology proper, is general, considering the questions of man's place in nature, and his origin, whether by special creation, or by derivation from preëxisting forms; and special, considering types, the classification and origin, the laws of the formation, development, death, and renewal of races. To the second division he gives the name of ethnography. It concerns the agglomerations of peoples, hordes, and tribes as we meet them. Its interest is derived from questions that are peculiar to it, and from the fact that races do not exist in nature, but are only abstractions, characterized by types which we imagine to have existed among ancestors. Nowhere can the real existence of a race be discovered, but we find two or three types, even among the most savage and most isolated tribes. Special ethnography relates to the description of each people; general ethnography to common questions of manners, customs, aptitudes, industries, beliefs, institutions; to the past of the race, the environment, circumstances in the evolution of humanity; to sociology. The third division includes the complementary sciences, among which archaeology, especially prehistoric archaeology, holds the first rank. It