618 



SCIENCE 



[N. S. Vol. XXXI. No. 799 



be built up from the investigations of a num- 

 ber of observers. Dr. Garrison closes his very 

 interesting account by saying : " But no one 

 ever thought of mosquitoes in relation to yel- 

 low fever before the time of Finlay and Wal- 

 ter Reed." Dr. Eeed and his associates 

 proved the theory, which was the all-impor- 

 tant event, but it may not be amiss to call 

 attention to an article published by Dr. 

 Josiah C. Nott in 1848. He was evidently a 

 learned physician of wide experience, a keen 

 observer and reasoner, and in addition had a 

 profound knowledge of the literature of zo- 

 ology, particularly entomology. To what ex- 

 tent he anticipated present knowledge of the 

 mosquito transmission of yellow fever may be 

 somewhat a matter of opinion. The article is 

 a most interesting one and will well repay 

 perusal. It should be read in its entirety to 

 get the proper conception of it and realize to 

 what a remarkable degree the man was ahead 

 of his day. The title is " Yellow Fever con- 

 trasted with Bilious Fever — Eeasons for be- 

 lieving it a disease sui generis — Its mode of 

 Propagation — Remote cause — Probable in- 

 sect or animalcular origin, etc., by Josiah C. 

 Nott, M.D., Mobile, Alabama. New Orleans 

 Medical and Surgical Journal, IV., pp. 563- 

 601, 1848." A few extracts may prove in- 

 teresting, as this journal is not accessible to 

 many persons. 



I propose to now show, from facts presented 

 during the various Epidemics in Mobile that the 

 morbific cause of Yellow Fever is not amenable 

 to any laws of gases, vapors, emanations, &c., 

 but has an inherent power of propagation inde- 

 pendent of motions of the atmosphere, and which 

 accords in many respects with the peculiar habits 

 and instincts of insects. . . . There are even per- 

 fectly autlienticated instances where one side or 

 end of a ship has suffered severely from this dis- 

 ease, whilst the other was entirely free from it! 

 We can readily believe, that certain insects which 

 are endowed with unaccountable instincts and 

 habits might attack a part of a ship, or a tree, 

 of a wheat or cotton field; but we can not imagine 

 how a gas could be turned loose on one side of 

 the cabin of a vessel and not extend to the other. 

 . . . Yellow Fever can not be explained by the 

 malarial' theory, and it must remain with the 



^Used in the sense of bad air. 



reader to determine whether the chain of analogies 

 offered, render the Insect theory more probable. 

 . . . With these facts before us, how much more 

 easily may we account for the spread of yellow 

 fever from a focus, by the insect, than by the 

 malarial' hypothesis — here is something tangible 

 and comprehensible. 



In regard to cholera he says : " The history 

 of these great epidemics which sweep over 

 the surface of the globe affords very strong 

 support to the Insect theory." Dr. Nott's re- 

 marks on vessel quarantine are in absolute 

 accord with the knowledge and practise of to- 

 day. Henry Skinner 



The Academy or Natukal 

 Sciences of PniLADEnPHiA 

 / 



DOES EXCESSIVE LIGHT LIMIT TROPICAL PLANKTON ? 



To THE Editor op Science: Among the 

 numerous explanations of the richness of 

 polar seas in plankton and the poverty of 

 tropical waters, I fail to see any mention of 

 the lethal eifect of excessive light, yet this 

 eifect is so well known that we make daily use 

 of sunlight to destroy pathogenic organisms, 

 all of which flourish in the dark only. The 

 tropics are rich in all land forms, but in every 

 case there is some provision by which the 

 protoplasm is protected from excessive light, 

 and, as a matter of fact, the ordinary bacteria 

 of northern latitudes do not flourish in the 

 tropics. In the waters, on the other hand, 

 uupigmented forms have nowhere to hide, as 

 in caves, crevices, under rocks or under the 

 shade of pigmented ones, except as parasites 

 in the bodies of multicellular organisms, and 

 must perish through this disinfecting power of 

 the sun's rays. The same phenomenon has 

 been found by the metropolitan sewage com- 

 mission in the waters of New York harbor, 

 where the winter flora derived from sewage is 

 far richer than the summer. 



The vernal increase of phyto-plankton in 

 northern waters is the same phenomenon as 

 the vernal increase of land plants — due to the 

 return of the sun with non-lethal amounts of 

 light which are utilized in the decomposition 

 of carbon dioxide by the chlorophyl. To be 

 sure, the increased temperature of the air is 

 the main reason for renewed protoplasmic ac- 



