470 



SCIENCE. 



[N. S. Vol. XXIII. No. 586. 



anastomose somewliat. They project into the 

 jelly tissue that fills the remainder of the 

 compartment. 



A remarkable feature is the striation of 

 the substance of the electroplax. Even in the 

 poor alcoholic material at my command, it 

 stands out almost as marked and clear as in 

 striated muscle, and it has much the same 

 structure. As in Baja, these lines of stria- 

 tion are parallel but not straight ; but, differing 

 from Raja, they have an intei-mediate line and 

 they are found in all parts of the papillaB and 

 up to the electric layer. The presence of so 

 much striated substance does not accord with 

 Ballowtiz's view of the specialization and effi- 

 ciency of electric tissue. That so small an 

 organ should give so marked a shock puts it 

 on a level with Oymnotus and Torpedo, both 

 of which are supposed to have specialized 

 their striated substance out of existence by 

 developing the network for greater power. 



However, it is not proper to go further into 

 the question until I have prepared fresh ma- 

 terial and studied the details of nerve endings, 

 ' rod-net,' and coarse and fine network. Mr. 

 0. F. Silvester has undertaken to work out 

 the gross anatomy as part of this paper. 



Ulric Dahlgren. 



Princeton University, 

 January 28, 1906. 



A NEW METHOD OF COLLECTING EARTHWORMS 

 FOR LABORATORY USE. 



For the benefit of teachers of biology who 

 use the earthworm as one of the laboratory 

 types it has seemed worth while to briefly re- 

 port a method which has been successfully 

 employed in my laboratory during the past 

 two years, and which in the saving of time 

 and labor we have found a very great im- 

 provement over the old methods of capturing 

 them at night by the aid of a lantern, or by 

 digging over the earth by means of a spade 

 or such implement. 



The method was first called to my attention 

 by the care-taker of the golf greens on the 

 university campus, who used a proprietary 

 article, sprinkling it over the greens, follow- 

 ing which the worms would emerge in great 



numbers from their burrows, and were then 

 swept up and destroyed, thus relieving the 

 surface of the annoyance of the castings. 



This preparation is known by the name of 

 ' Eushmore's Concentrated Worm Destroyer,' 

 and may be had by the barrel of the manufac- 

 turer. Garden City, N. T. It is, as indicated, 

 a concentrated liquid, and for use must be 

 diluted with about one hundred and fifty 

 times its bulk of water. In using, it is simply 

 sprayed over the lawn, where worms are 

 known to abound, from an ordinary watering 

 pot till the surface is well saturated. Within 

 five minutes, usually, the worms begin to 

 emerge from their holes and may be collected 

 and placed at once in clean water, which 

 should be changed several times in order to 

 remove all trace of the irritant, in order that 

 they may not distort themselves and thus be 

 injured as specimens. They may then be 

 narcotized after the usual method and pre- 

 served in either alcohol or formalin. In using 

 such specimens for dissection they have been 

 found to be quite as good as those taken by 

 older modes of collection. 



We have found it quite important to use a 

 greatly diluted preparation, otherwise it tends 

 to drive the specimens deeper into the burrows 

 and thus fail of its object. 



Commenting upon the method among some 

 of the students it was discovered that similar 

 methods have been used by others, though 

 involving greatly differing media. For ex- 

 ample, it was said that when using a very 

 dilute solution of corrosive sublimate, one part 

 in ten thousand, for killing potato ' bugs,' in 

 many cases earthworms would emerge in the 

 same manner as in the former. Again, it was 

 also learned that to obtain angle worms for 

 bait a decoction of mustard in water had been 

 sprinkled over the ground, in response to 

 which specimens would readily come to the 

 surface. 



It would seem, therefore, that probably any 

 of several such means might be employed 

 successfully. The proprietary article has a 

 considerable use among keepers of golf links, 

 and where so used one may easily take advan- 



