26 



SCIENCE. 



[YOL. VI., No. 127. 



continue to be those indicated in the sentence 

 above quoted. 



Whatever the yellow-fever poison may ulti- 

 matel}' prove to be, enough is already known 

 of its characteristics and limitations to enable 

 us to formulate specific measures of such pre- 

 caution. For practical purposes, we are not 

 concerned with the many theories regarding its 

 origin, — whether it was first engendered dur- 

 ing the horrors of the ' middle passage ' in 

 the hold of an African slaver, or in the putre- 

 faction of the abundant marine life of the Sar- 

 gossa Sea, or b}^ the action of atmospheric 

 forces peculiar to the equatorial Atlantic, or 

 b}^ the spontaneous development of a specific 

 organism. It is suflScient to know that there 

 is such a poison, and, 1°, that while it does 

 not originate in this country, it may be con- 

 veyed from place to place ; 2°, that it is a 

 poison of considerable specific gravit}^, infect- 

 ing the lowest stratum of the atmosphere, and 

 possesses great tenacity, clinging to surfaces ; 

 3°, that it flourishes amidst filth, under certain 

 conditions of temperature and moisture ; and, 

 4°, that the disease which it produces is essen- 

 tially one of cities and crowded populations. 



Upon these characteristics must be based the 

 precautions to be enforced, and first with re- 

 gard to communication with places where the 

 disease is endemic. A quarantine of absolute 

 exclusion is demonstrabh' impracticable, owing 

 mainly to the man}' facilities which steam en- 

 ables commerce to command. Much, however, 

 ma}^ be done in this direction b}^ a quarantine 

 of inspection and sanitation. To this end it is 

 necessar}^ that, within the geographical limits 

 where yellow-fever ma}' become epidemic in 

 the United States, a system of sanitar}^ super- 

 vision over personal and commercial inter- 

 course with places where the disease exists 

 endemically be established and maintained 

 during the season when the atmospheric condi- 

 tions necessary to its epidemic spread obtain 

 in this countr}'. This would dictate specifi- 

 call}^ that such supervision over commerce with 

 South- American ports lying north of 22° south, 

 with the West Indies and the Bahamas, and 

 with the east coast of Mexico, should begin in 

 April at the Gulf and South- Atlantic ports, and 

 in May at ports north of 32° or 33° north, 

 and should continue until the close of October 

 and September respectivel}'.^ 



1 Of a hundred and seventy -four epidemics, of which the date 

 of beginning has been accurately recorded, three began in May in 

 places south of latitude 33° north, but none earlier than June in 

 places north of Charleston (32° 46' north) : four began as late as 

 October in the former, but none later than September in the lat- 

 ter. Hence south of Charleston the danger season begins in 

 April, and ends in October : north of Charleston it begins in May, 

 and ends in September. 



The supervision should consist of an inspec- 

 tion of every vessel arriving from the region 

 specified, and of treatment, which will vary, 1°, 

 with the actual sanitary condition of the vessel, 

 her cargo, belongings, and personnel^ includ- 

 ing in the sanitary condition the facts as to 

 age, material, and previous j^ellow-fever his- 

 tory ; 2°, with the sanitary status of the port of 

 departure ; and, 3°, with the climatic and other 

 conditions of the port of arrival. Within the 

 limits assigned to this paper, it is not possible 

 to enter into the details of this treatment. 

 They are well understood by practical sanitari- 

 ans, and their suflScienc}' has been demonstrated 

 b}" the inspection services of the National 

 board of health and the Sanitary council of the 

 Mississippi valle}^ as well as in the quarantine 

 practice of the port of New York and else- 

 where ; while a practical test of their value for 

 the protection of the port of New Orleans is 

 now being made by the Louisiana state board 

 of health. The characteristics of the poison, 

 as set forth in the second and third proposi- 

 tions, will indicate what methods of treatment 

 by disinfection and cleansing are necessary.^ 



But no matter how perfect such a sj^stem of 

 sanitary quarantine may be made, there is 

 alwaj's the risk of the poison being introduced 

 through some unsuspected, and therefore un- 

 guarded, channel.^ To meet this risk leads to 

 further consideration of the third proposition, 

 — that the poison flourishes amidst filth. 



Whether the disease is in its indigenous 



1 Assuming that yellow-fever is •' due to a specific cause 

 which is capable of growth and reproduction," and which is 

 transportable, not only by adhesion to surfaces, but in the air 

 from an infected locality ; and that the " growth and reproduction 

 of this cause [i.e., the yellow-fever poison] is connected with the 

 presence of filth, in the sanitary sense of that word, including 

 decaying organic matters and defective ventilation," — it follows 

 that closed vehicles, compartments, or receptacles, and articles or 

 masses of material capable of retaining air motionless in meshes, 

 folds, webs, or interstices, are dangerous as contagion-carriers in 

 proportion as their character, use, or structure prevents or 

 retards aeration, and in proportion as such articles or materials 

 furnish organic matter liable to decay: hence an empty box- 

 car, or the unventilated hold of a vessel in ballast, may be the 

 means of introducing the poison by transporting infected atmos- 

 phere . . . [extract from a " Memorandum for the classification 

 of articles of merchandise for quarantine purposes," drawn up by 

 the writer, and adopted by the Sanitary council of the Mississippi 

 valley, April 21, 1881]. 



It will be seen from the above that the disinfection necessary 

 for yellow-fever is essentially different from that laid down by 

 the recent International sanitary conference at Rome as suffi- 

 cient for cholera. In the report of the committee of that con- 

 ference on the question of disinfection, and which embraces 

 such eminent men as Koch, Sternberg, and Proust, it is specifi- 

 cally stated that ' disinfection of merchandise and of the mails 

 is unnecessary; ' while, of atmospheric disinfection, no mention 

 whatever is made in the report. That these are both essential 

 for yellow-fever, is, in the opinion of the writer, beyond ques- 

 tion. His personal experience during the epidemics of 1878-79 

 alone — notably , that on the relief-boat Chambers, in connection 

 with the infection of Lieut. Benner and others — is to him con- 

 clusive on this point. 



2 Intercommunication with Mexico by rail, for example, 

 suggests one mode which as yet has not been provided against ; 

 although an extension of the system of sanitary supervision to 

 railroad intercourse is entirely feasible, as has been shown dur- 

 ing the past few years by the operations of the inspection ser- 

 vices above referred to. 



