64 



SCIENCE. 



[N. S. Vol. XII. No. 289. 



their meaning because of the special char- 

 acter of the subject in the discussion of 

 which they are employed. 



The terms hypocotyl and epicotyl of 

 Darwin, and hyponasty and epinasty of 

 DeVries are objectionable because, being 

 respectively antithetical terms, they are 

 wanting in correlative construction. That 

 is, in their derivation, iTzl, upon, to, or to- 

 ward, is made the antithesis of 6-6, below, 

 or under ; whereas 6-ip, above, or over is 

 the proper antithesis of 6-6. Therefore if 

 hypocotyl is used, its antithetic correlative 

 should be hypercotyl ; and similarly the 

 correlative of hyponasty should be hyper- 

 nasty. 



Not only are the terms hypocotyl and epi- 

 cotyl etymologically defective, but their use 

 as originally proposed is not always struc- 

 turally appropriate . Darwin proposed these 

 terms to indicate the up-growing and down- 

 growing portions respectively of the germi- 

 nating plantlet, and it is evident from his 

 use of them that he assumed the axis be- 

 tween the opposing portions to be practi- 

 cally identical in position with the points 

 of attachment of the cotyledons. As a 

 matter of fact, however, the cotyledons do 

 not mark any material division in the struc- 

 ture of the plantlet, and the axis referred to 

 is quite independent of their position. In 

 many plants, the bean, for example, the 

 axis is much below the cotyledons and the 

 latter therefore rise above ground as the 

 plantlet grows ; while in many other plants, 

 the pea for example, the axis is above the 

 cotyledons, and the latter therefore remain 

 underground. For this inconspicuous, but 

 real, dividing disk between the up- growing 

 and down-growing portions of the plantlet, 

 and also of the mature plant, I have long 

 personally used the term tropaxis, of par- 

 tially Latinized Greek derivation ; and for 

 the parts above and below the axis I have 

 used the adjective terms apotropic, and epi- 

 tropic respectivelj'^. 



The terms proposed by Frank, Darwin, 

 DeVries and others have passed into the lit- 

 erature of botany with all their excellencies 

 and imperfections, while my terms apotrop- 

 ism,epitropism and tropaxis have never been 

 published although I have for more than 

 thirty years accustomed myself to their use. 

 I still think they have much merit and 

 therefore oifer them for consideration in 

 connection with suggestions for correcting 

 the structure and use of certain terms now 

 generally employed. 



Charles A. White. 



Smithsonian Institution, 

 June 25, 1900. 



LYMPSOSPOEIDIUM TEUTT^E, NOV. GEN., 

 NOV. SPEC. THE GADSE OF A BECENT 



BROOK TROUT EPIDEMIC. 

 In October, 1899, my attention was called 

 to a disastrous epidemic among the brook 

 trout in a Long Island hatchery. The first 

 evidence of the epidemic was seen in May, 

 1899, when the director picked out a dead 

 fish from one of the ponds and saw that one 

 side was pierced by a clear-cut hole. Think- 

 ing the hole due to some bird like a king- 

 fisher, he threw the fish away without 

 further thought. When, however, he found 

 other dead fish with similar wounds, and 

 when the death-rate became noticeably 

 large, an attempt was made to stop the 

 headway of what was then recognized as a 

 disease. Precautionary measures were use- 

 less, and during the summer the fish died 

 off at the rate of hundreds per day. ISTor 

 did the disease stop until, in December, 

 every fish iu the ponds had died. 



Investigation begun in October showed 

 the cause of the trouble to be a hitherto un- 

 described genus of parasitic Protozoa, which 

 I havenamed Lymphospoi-idiumtndtcejhelong- 

 ing to the same class (Sporozoa) as the ma- 

 laria germ, although the effects of the par- 

 asite on the fish are in no way similar to 

 the effect of the malaria-organism in man. 

 Evidences of the disease in the fish were 



