July 10, 1885.] 



SCIENCE. 



25 



it would seem, at first view, that the increased 

 rapidity of travel would also disseminate more 

 rapidly the scourges ; and yet it has seemed to 

 me the practical working is the reverse. Those 

 familiar with the history of cholera among the 

 Mohammedan pilgrims are aware that since 

 the abolition of caravans, and the transporta- 

 tion of pilgrims by steamers, very many fewer 

 cases of cholera occur at Mecca, and along 

 the land route from Dejeddah. It is because 

 all are kept, so to speak, in a certain lane, 

 where they are under constant observation ; 

 their food and h3'gienic surroundings are 

 more carefullj^ regulated ; and cases occurring 

 can be promptly treated and guarded. The 

 same is true of steamers bringing emigrants 

 to this country. With competent medical of- 

 ficers, isolated hospitals, absolute cleanliness 

 of attendants, and prompt disinfection of dis- 

 charges, the disease should be limited to those 

 who had contracted it before coming onboard, 

 and virtually suppressed by the time of their 

 arrival at any one of our seaports. 



This influence of steam-communication is 

 more striking, though in a different wa}^, with 

 reference to yellow-fever. In the great majori- 

 ty of cases, the vessel is the means of transpor- 

 tation ; and the particular place of preference 

 for the poison is, as stated above, in the filth 

 which accumulates in the bilge. In sugar and 

 milado carrying vessels, this, in a tropical cli- 

 mate, soon develops fermentative action. Until 

 within a few years, the commercial history of 

 vessels trading with yellow-fever ports has been 

 as follows : A European cargo is taken to Ha- 

 vana, discharged, and the vessel lies an indefi- 

 nite time empty in an infected port, seeking 

 a charter for some seaport in the United 

 States. No particular precautions of clean- 

 liness are taken, either as regards the vessel 

 or the crew. In most cases the fever appears 

 while lying in port. A cargo is at length 

 obtained, which adds to the filth of the bilge 

 already infected. A better nidus for the prop- 

 agation of the poison could not be formed ; 

 and under a tropical sun, sealed hatches, and 

 stagnant air, it intensifies with great rapidity. 

 An experience of several years showed that 

 the majority of cases brought to the port of 

 New York were on vessels of this character. 

 Within the past ten years a radical change has 

 been going on, and steam- transportation has 

 largel}^ replaced sailing-vessels, and with it 

 there has been a large diminution in the num- 

 ber of the cases of 3'ellow-fever. Steamers be- 

 long to regular lines, which make frequent and 

 regular trips, remain but a short time in port, 

 and are therefore rarely infected. Being of 



iron, their construction enables one to reach 

 the bilge with facilit}^, while the steam-pump 

 flushing it keeps it clean : there is no wood to 

 saturate and become infected. A steamer, 

 too, carries the cargo of several sailing-vessels, 

 and lessens the risk in that proportion. So 

 far, then, from the rapidity of steamers facili- 

 tating the spread of cholera and yellow-fever, 

 they have been the means indirectly of retard- 

 ing both. 



It could also be easily shown that the long 

 antagonism between commerce and quarantine 

 has entirely passed away. Instead of vessels 

 riding an indefinite quarantine, our knowledge 

 of the natural history of the two diseases tells 

 us that the sooner a A^essel is emptied, the less 

 the danger of transmission of disease. Vessels, 

 therefore, in quarantine, are returned to com- 

 merce sooner than if they went to dock, and 

 discharged through the usual routine. 



S. Oakley Vanderpoel, M.D., LL.D., 

 Professor of hygiene, medical department, 



University of the city of New York. 



HOW TO DEAL WITH YELLOW-FEVER, 



In closing a report on the yellow-fever epi- 

 demic of 1873, made in response to a resolu- 

 tion of the U. S. senate, the present writer 

 used the following language : — 



" It may finally be added, that, in the absence of 

 other adequate cause, the gradual narrowing of the 

 yellow-fever zone in the United States during the 

 past fifty years — say, from the time when leases in 

 New- York City frequently contained a provision for 

 reducing the rate of rents in the event of a depres- 

 sion of business from the advent of cholera or yel- 

 low-fever — may be fairly claimed for the sanitarian 

 and his efforts; and that in such efforts lies all there 

 is of promise for the future in dealing with yellow- 

 fever." 



This was written before the brilliant results 

 of the investigations of Pasteur and Koch had 

 opened up the tempting field which Ferran and 

 Domingos Freire already claim to be success- 

 fully cultivating. It may be that these gen- 

 tlemen have actually accomplished — the one 

 for cholera, and the other for yellow-fever — 

 what Jenner, Pasteur, and Koch have done 

 for other diseases ; and although this is not 

 3'et proven, and, in the nature of the case, will 

 require considerable time to demonstrate, there 

 is scientific ground for believing that immu- 

 nity against these pestilences will eventuallj' 

 be secured through a process analogous to that 

 by which vaccination has disarmed small-pox 

 of its terrors. Until that desideratum is 

 reached, however, the precautions which should 

 be taken to provide against yellow-fever will 



