64 



SCIENCE. 



[Vol. X. No. 235 



The results of this journey are confirmed and supplemented by the 

 observations of the Pundit A-K, who visited Lhasa, and, continu- 

 ing his journey farther north, reached Tsaidam. 



In 1884 and 1885 Prejevalsky accomplished his fourth journey in 

 Tibet. From Kiachta he went to the Chinese city of Sining-, east 

 of the Koko Nor. Having arrived in eastern Tsaidam, he left all 

 his superfluous baggage under the charge of seven Cossacks, while 

 he and his companions, a party of fourteen, started to explore the 

 sources of the Hoang-Ho, which is situated in a plateau from 14,000 

 to 1 5,000 feet in height. Travelling south, Prejevalsky crossed the 

 divide between the Hoang-Ho and Di Chu, the source of the Yang- 

 tse-Kiang, at a height of 14,500 feet, and, on entering the basin of 

 the Di Chu, came to a country alpine in its character, but without 

 forests, possessing, however, a rich and varied herbaceous flora. 

 From here he returned to Tsaidam, and, turning west, made the 

 important discovery of the ' Valley of the Winds,' which gradually 

 rises to an easy pass across the Taguz Daban Mountains, leading 

 to Cherchen. This pass, and the route from Sha-chau along the 

 foot of the Altin Tagh, were the caravan routes used in former times 

 in the trade between Turkestan and China. From here he paid 



Fig. 2. — Salt Marshes in Tsaidam. 



another visit to the Lob Nor, and then returned to Russia by way 

 of Cherchen, Kiria, and Khotan. 



Our map shows the important results of these journeys ; but be- 

 sides this, other recent researches have been made use of in con- 

 structing the map. The sources of the Irawadi and the adjoining 

 parts show Colonel Woodthorpe's explorations. The north-western 

 part is from the Indian Trigonometrical Survey map of Turkestan, 

 but corrected according to th& recent Russian surveys on the Pamir 

 and the adjoining regions, and to the surveys of the Afghanistan 

 Boundary Commission, as far as they have been published. 



HEALTH MATTERS. 

 Health in Schools. 



The Medical Society of the State of New York voted at its an- 

 nual meeting to distribute fifteen hundred copies of the essay of Dr. 

 A. N. Bell, on the physiological condition and sanitary requirements 

 of school-life and school-houses, which received the Merritt H. 

 Cash prize at the annual meeting held in February. These addi- 

 tional copies are intended for the school-officers of the State, and if 

 read, and the advice therein given is put into practice, much good 

 will result. The essayist opens by calling attention to the plasticity 

 of every living organism during the early period of its existence, and 

 to the liability of causing constitutional weakness, or even a dis- 

 eased state, if a young person of originally healthy constitution be 

 subjected for a considerable period to such injurious physical con- 

 ditions as tend to produce a modification of type. All the phe- 

 nomena of maintaining a living existence are accomplished by the 

 process of nutrition. The parts played by respiration and the blood 

 in this process receive due attention from the essayist ; and the 



nervous system, including the brain, is concisely described, both as 

 to structure and function. 



In speaking of the age at which children should be sent to 

 school. Dr. Bell says children differ greatly in their powers of resist- 

 ance to injurious influences, as do adults, though incomparably 

 more susceptible to them : hence to fix upon the age at which 

 school-life may be commenced involves the consideration of the 

 kind of school-life as well as the adaptation of the child. The first 

 and central fact to be constantly kept in view in conducting school- 

 life is the plastic property of the child's mind. This fact being al- 

 ways uppermost, healthy children, at the age of about seven years, 

 may safely begin to learn the alphabet, spelling, and figures, on the 

 kindergarten system, giving them not more than two or three 

 hours' application daily, with not less than half of the time, at equal 

 intervals, for play ; provided, always, the sanitary conditions of the 

 school-room are duly regarded. At the age of about ten years, 

 systematic education may be commenced ; but up to the age of 

 puberty, the school-time should not be more than six hours daily ; 

 and no child should be required to devote more than half of the 

 time of school-hours to study, or more than forty minutes at a time 

 to close application ; and no recitation or blackboard exercise, 

 which imposes the greatest exertion of the mind, should be longer 

 than fifteen minutes. The education of the senses, and the best 

 kinds of gymnastics for school, are considered quite at length. 



There is one point upon which Dr. Bell lays great stress, and we 

 are gratified that he does so ; that is, the punishment of a refractory 

 pupil by his detention from play, or keeping him in after school- 

 hours. He says that teachers and others who favor the keeping-in 

 system must be very superficial observers of children, not to have 

 learned that to deprive a child of play is an exceedingly poignant 

 punishment, — one that afflicts and grieves his mind not only, but 

 frequently stirs up his worst passions. Besides, keeping-in is fre- 

 quently coupled with an extra task, or ' till the lesson is got.' 

 Surely, nothing could be better calculated to create a repugnance 

 to study, and stimulate obstinacy. Moreover, it sometimes involves 

 the loss of a meal, or, at least, a postponement of meal-time, to the 

 derangement of digestion and injury of health. In every attitude of 

 the case the system of keeping-in as a punishment is bad ; worse, 

 even than corporal punishment, and, like it, should never be prac- 

 tised except in extreme cases. 



In the portion of the essay devoted to the school-house itself, the 

 site first claims attention. In dealing with this subject, the essayist 

 says that the ground air is liable to be impregnated with emana- 

 tions from all decomposing material ; and instances are by na 

 means lacking to show that schools exposed to such dangers 

 have frequently incurred severe epidemics of whooping-cough, 

 measles, scarlet-fever, diphtheria, and typhoid-fever, and are con- 

 stantly liable to pneumonia, catarrhal and diarrhceal diseases. In 

 speaking of the materials which should be selected to be used in 

 building school-houses. Dr. Bell refers to the examination of various 

 kinds of stone which was made with reference to the choice of 

 building-stone for the British House of Parliament in 1839. It was 

 then found that the absorption of water for one hundred volumes 

 of rock was in the following proportions : in three specimens of sili- 

 ceous limestones, 5.3, 8.5, and 10.9; three of nearly pure limestones 

 from oolite, 18.0, 20.6, and 31.0. In all the experiments the air was 

 removed by first placing the specimens in water under the vacuum 

 of an air-pump. Brick, under the same process, will absorb from 

 ten to thirty volumes of water. The ventilation, warming, and 

 sewerage of school-houses are concisely and intelligently discussed. 



In speaking of the sanitary surveillance which is so essential in 

 every school-system. Dr. Bell's testimony is of great value. His 

 experience as a member of the Board of Education in Brooklyn en- 

 titles him to speak ex cathedra. He says, that, constituted as our 

 boards of education are, with few exceptions, though there may be 

 some members who are physicians, it is impracticable to secure 

 competent sanitary supervision under the direction of or subordi- 

 nate to them. They are generally divided into committees with 

 special charges, — on sites, construction, heating, ventilation, 

 health, etc. ; and on school-houses, with the special surveillance of 

 particular schools, severally, to the different committees. All such 

 committees are exceedingly jealous of their rights, and resist the 

 interference of their fellows : hence even inquiries are commonly met 



