185 



a correct analysis of every sample of fertilizer sent to him by the commissioner ; 

 and every farmer in the State can obtain the services of the chemist, free of 

 cost, to test the gnarantee of the maunfactnrer ; and if the goods do not come 

 «p to the guarante(>. llu' law releases the i)ur<-haser from any obligation to pay 

 for the fertilizer. 



BULLETIN No. 9 (NEW SEKIES). DECEMBER. 1889. (SCIENCE CON- 

 TRIBUTIONS. Vol. 1. No. 1.) 



Ne:matode root-gat.ls, (}. V. Atkinson, Ph. B, (pp. 5-54) (illus- 

 trated). — A i^reliniinary report upon the life history and metamor- 

 phoses of a root-gall nematode, Heterodera radicicoTa (Graef), Miill., 

 and the injuries caused by it upon the roots of various plants. This 

 is the first number of a series of publications entitled "' Science Con- 

 tributions," in Avhich it is proposed to publish reports of the more 

 stricth' scientific researches conducted at this Station. It contains a 

 preliminary report on investigations made in the autumn of 1889 on 

 the nature and causes of the abnormal growths on the roots of various 

 plants, termed root-galls or root-knot. The subject is treated under 

 the following topics: Introductory; external characteristics of the 

 disease; microscopical characteristics; general characteristics of the 

 mature female cyst; development and metamorphoses; structural 

 characteristics of the diseased roots; treatment; list of thirty-six 

 kinds of plants aifected; list of thirty-six American and foreign 

 works consulted; and explanations of plates. 



The bulletin is illustrated with six plates containing nuuierous dia- 

 grams of the worms in different stages and of the diseased portions of 

 various plants. There is also a consideralile number of references to 

 European and American j)ublications on these and kindred topics. 



Eoot-galls have been found by the author on thirty-six different 

 kinds of plants in the vicinity of the Station. Among those on which 

 they were ol^served most numerously are potatoes, tomatoes, cow-peas, 

 sunflowers, water-melons, cabbages, ruta-bagas, parsnips, and salsify. 

 " Upon examination with the microscope the enlargements proved to 

 be the galls produced by the presence of a nematode worm, Heterodera 

 radicicola, Miill. {AnguiUula radicicolcu Graef, AnguiUula arenaria, 

 N., ex jHirte).'"' 



Brief recapitulation of the life hiatonj. — Efiii: The oblong, bean-shaped egg, 

 .08""" to .10""" long, develojied in the anterior part of the ovaries, after fertiliza- 

 tion, inclosed in a double-walled menjbrane, undergoes partial or complete seg- 

 mentation while yet within the uterus. From the beginning of segmentation to 

 the fully developed larva five to seven days are required. The thread-like larva 

 is coiled three or four times within the egg membrane. Larva: At the time of 

 hatching or soon thereafter it molts for the first time. It is " thread-like,'' blunt 

 at the head end, and narrowly pointed at the tail end, .3"""' to .4"'"' long. In the 

 head end can be easily noted the exsertile spear anrl the long tortuous channel of 

 the anterior part of the oesophagus extending to a prominent ovoid or ellipsoid 

 nmscular bulb, the middle part of the oesophagus. From this point the lumen 

 of the alimentary canal can be seen extending down through the middle of the 



