January 6, 1888.] 



SCIENCR 



air. Dust is attracted from warm air to a cold body. If that body- 

 is wet, it adheres. By canopies of mosquito-netting over the sick- 

 bed, kept wet with bichloride-of-mercury solution containing gly- 

 ■cerine, no dust can pass through the meshes in either direction. 

 The cooled threads attract across the narrow space of the mesh all 

 dust that reaches there. The glycerine and water fix it, and the 

 corrosive sublimate sterilizes it. To keep up the application, two 

 layers of netting are required, — ■ one fixed, the other removable. 

 The outer removable one can at stated times be wrung out of a 

 fresh solution, and put back again. Overlapping folds can allow 

 the passage of food, medicine, etc., to the patient. This provides 

 perfect isolation even in a room occupied by others." 



R. Harvey Reed, M.D., Mansfield, O., secretary State Sanitary 

 Association, has known cases where old rags taken and sold from 

 scarlet-fever cases have been used by wipers, and they in turn have 

 communicated the disease to their families. He could give many 

 others if it were necessary, but this fact has long since been estab- 

 lished. 



D. S. Kellogg, M.D., Plattsburgh, N.Y., believes that the disease 

 may arise de novo, and bases his belief on the ground that he has 

 had cases which he cannot reaso7iably determine, after careful in- 

 vestigation, originated from any previously existing case. He says, 

 ■" I believe scarlet-fever to be communicable, yet last spring my belief 

 received a severe blow. My little boy, aged six, was severely 

 sick with this disease. My baby, aged three, slept across the hall ; 

 and my son, aged eight, slept down stairs. The sick boy was kept 

 in a room by himself. Yet his mother and I were constantly going 

 from the sick one to the well ones, and not either one of them took 

 the disease. The sick boy ' peeled ' so thoroughly that the sheets 

 had to be shaken in order to get rid of the fine flakes of skin. He 

 had many toys that he played with after convalescence set in. I 

 disinfected the room in about six weeks from the beginning of his 

 sickness, and the toys. He and the two other children have played 

 with these toys ever since, have slept in the room for a number of 

 months, and have not had any further scarlet-fever." He does not 

 believe that any thing can be done by the use of remedies to prevent 

 well persons from contracting the fever. He believes that if a person 

 has been exposed to scarlet-fever, the better his physical condition, 

 the better is he able to endure the disease. There are many instances 

 that would make this not seem true. 



T. D. Crothers, M.D., Hartford, Conn., says, " In 1868 I traced 

 in an epidemic twenty-one cases to contagion clearly. The com- 

 municability was by contact in most cases ; in others it was through 

 the near association. In two instances a Unen picture-book was 

 the medium of communication of the poison. In several cases it 

 was taken by the clothing of persons who had been nursing such 

 cases. Clothing has retained this infection several weeks when 

 confined in a trunk. Many cases have occurred in a community, 

 and been confined to a single case by means of isolation, quaran- 

 tine, disinfection, and extreme cleanliness." 



William H. Brewer, professor in Sheffield Scientific School of 

 Yale University, New Haven, Conn., in reply to the question whether 

 scarlet-fever ever arises de novo, says, " There are insufficient 

 data for a positive belief. From the evidence, however, that we 

 have, I say no, until better evidence is brought forward that it 

 does arise de novo. Quarantine the cases if public opinion will 

 justify : if not, then the first duty of the board is to educate the 

 pubhc as to the facts and the dangers. So soon as the public is 

 ready for it, scarlet-fever will be more rare than the small-pox. 

 But before this can be brought about, there must be a strong public 

 feeling that it is a controllable disease." 



W. C. Van Bibber, M.D., Baltimore, Md., thinks that boards of 

 health should endeavor to change the non-sanitary condition of 

 neighborhoods and places ; for, although scarlet-fever may not now 

 be fairly numbered among the filth-diseases, yet cleaning and sani- 

 tary laws may do good on general principles. Cleaning, segrega- 

 tion, and belladonna internally, ventilation, and increased vigor by 

 increasing the vigor of individuals, should be employed. He 

 says, " I attended Christ Church Charity School, Baltimore, for 

 thirty-six years. The means above mentioned were used where a 

 case of scarlet-fever occurred. The school consisted of thirty-two 

 children. In thirty-six years there was but one death. The dis- 

 ease appeared in the school more than twenty times, and was al- 



ways kept confined to but few children by means of these precau- 

 tions. By personal hygiene, continued life in open air, the use of 

 belladonna internally to those exposed, and rubbing the diseased 

 body with disinfectants, much may be done to prevent the spread 

 of the disease. I combine in an oil embrocation (thymol, anise-oil) 

 carbolic and salicylic acids, and camphor. 



DO FORESTS INFLUENCE RAINFALL? 



It is very generally believed that the culture of forests induces an 

 increase in rainfall, and that their destruction diminishes it. A 

 satisfactory explanation of this supposed phenomenon has never, as 

 far as I am aware, been offered ; and the only tangible support for 

 the theory appears to consist in a few observations of rainfall in 

 limited areas in central Europe, made before and after reforesting. 

 It seems desirable that the question should be tested by all the evi- 

 dence at hand, arid the theory established or disproved by the 

 facts. We have in this country the material for testing both 

 phases of the theory upon a large scale and in an exhaustive man- 

 ner. 



The prairie region, including Iowa, northern Missouri, southern 

 Minnesota, most of Illinois, and a small part of Indiana, has, during 

 the past thirty years, undergone a great change with respect to its 

 vegetation. This great area of over 100,000 square miles, was, 

 when settlement commenced, mainly grass-covered. It contained 

 no forests. Belts of trees were found along the water-courses, 

 upon the slopes of river-bluffs, and here and there upon the slight 

 elevations. But man has encouraged the growth of trees, and the 

 area of arborescent vegetation has been greatly increased. It is an 

 example of reforesting upon an immense scale, unequalled else- 

 where upon the globe. Has the rainfall correspondingly in- 

 creased .'' 



The early settlers in Ohio found it mainly a forest-covered 

 region. It has been remorselessly cleared. This area of 40,000 

 square miles does not contain to-day a tithe of the timber-land 

 that it contained fifty years ago. Has the rainfall diminished 1 



The States of Massachusetts, Rhode Island, and Connecticut, 

 with adjacent parts of New York, New Hampshire, and Maine, — 

 an area of perhaps 25,000 square miles, — were, when Europeans 

 entered them, densely covered with forests. In time these were al- 

 most entirely cleared away. In recent years, however, a change in the 

 occupations of the people of this densely settled region, in virtue of 

 which the farms are being abandoned, while the inhabitants are 

 becoming massed in the cities, has allowed an enormous increase 

 in the wooded area of these States. To-day at least half this area 

 is again covered with woods. 



If this theory be correct, the rainfall in this region should have 

 diminished from the colonial times down to, say, i860, while since 

 that date it should have been on the increase. Are these the 

 facts ? 



We have here three areas of considerable magnitude, in which 

 radical changes in the forest-covering have been made during the 

 present century. Fortunately, also, we have ample records of the 

 rainfall during these periods. 



First, however, a word as to the character of the rainfall. Of all 

 current meteorological phenomena, rainfall is the most irregular, 

 both as to time and place. The rainfall of one year may be double 

 or treble that of the year before or the year following. At any one 

 station these fluctuations are ordinarily so great as to thoroughly 

 mask any secular change. It may vary greatly from place to place, 

 even though the distance be small, while the change of the location 

 of a gauge from the ground to the top of a house may make it give 

 very different indications. For these reasons it is apparent that 

 reliable results, in regard to a general increase or decrease of rain- 

 fall, are to be obtained only by combining a large number of obser- 

 vations scattered over many years and over the greatest possible 

 variety of conditions. It is a very easy matter to so select stations, 

 and years of observation, as to obtain any pre-arranged result. 



If there has taken place a change in the amount of rainfall in 

 any or all of these regions, it must, in the nature of things, have 

 been a progressive one, however disguised by sporadic fluctuations. 

 Moreover, if this increase or decrease in rainfall produces the re- 

 sults claimed for it, making a desert fruitful, or the reverse, it must 



