Maech 25, 1910] 



SCIENCE 



475 



intensity on opposite sides of a pseudopod induce 

 difference in rate of streaming so as to cause it 

 to bend. Orientation is due to the inhibition of 

 the formation of new pseudopods on the more 

 highly illuminated side of the body of the amtEbEe, 

 not to any effect on those already formed. 

 Colored Lights of Equal Intensity for Biological 

 Work: G. H. Pabkeb and E. C. Day, Harvard 

 University. (Presented by title.) 

 Colored light was produced by passing the light 

 from a Nernst lamp through a solution of an 

 appropriate aniline dye contained in a plate-glass 

 cell and used as a screen. In this way blue, green, 

 yellow and red lights of fair spectroscopic quality 

 were obtained. The intensity of these lights was 

 measured in terms of energy (heat) by means of 

 a radiomicrometer which was accurate to within 

 2 per cent. The stronger lights were then reduced 

 by being placed at such distances from the ani- 

 mals experimented upon that all lights were of 

 equal intensity at the spot where the animals 

 were. It was proposed to extend this method to 

 spectral light. 



Notes on the Behavior and Reactions of Amphi- 

 oxus: L. HussAKOP. (Introduced by Bashford 

 Dean, American Museum of Natural History.) 

 These experiments were carried on at the Naples 

 station during last September. They dealt with 

 the behavior of amphioxus and its reactions to 

 light, heat, chemical and mechanical stimuli. In 

 some reactions the Neapolitan species, Branchio- 

 stoma lanceolatum, behaves differently from the 

 Bermuda form, B. caribicEum, notably in regard 

 to heat. The former is adapted to a temperature 

 ranging from 35° C. to — .5° C, while the latter 

 (as shown by Parker) will survive only within 

 the limits of 42° C. and 4° C. 

 The Movements of the Earthworm — A Study of a 

 Neglected Factor: Seegids Mokgulis. (Intro- 

 duced by G. H. Parker, Harvard University.) 

 While studying reflex reactions of the earth- 

 worm I have been impressed with the fact that 

 the worm tends to move in a straight direction, 

 and, once having assumed such a course, it main- 

 tains itself obstinately in the path. This simple 

 observation was substantiated by special experi- 

 ments where, with the aid of an apparatus con- 

 structed for this purpose, the anterior or pos- 

 terior part of the worm was deflected either to the 

 right or to the left from the straight course. By 

 turning the tail to the right, for instance, the 

 head would be caused to turn to the left, and vice 

 versa. The position of the tail could be changed 



several times successively, first to the right, then 

 to the left, etc., and the head would likewise 

 change its position but in an opposite direction. 

 The extent of the orientation reaction of the head 

 was found to be directly proportional to the length 

 of the posterior part of the worm deflected from 

 the straight course; while the degree of deflection 

 of the posterior part necessary to occasion a bend- 

 ing of the head in an opposite direction is in- 

 versely proportional to the length of this part. 

 Depending upon the relative position of its tail, 

 the earthworm responding to unilateral stimula- 

 tion turns either towards or away from the 

 stimulus until it has assumed a straight position, 

 and then it begins creeping in that direction. 

 The Leucocyte Content of Milk: R. S. Beeed, 



Allegheny College. 

 Studies upon the Nerve Cells of Invertebrates: 

 W. M. Smallwood and C. G. Rogees, Syracuse 

 University. 



The nerve cells of all invertebrates so far ex- 

 amined, including representatives of more than 

 twenty genera of molluscs, worms and Crustacea, 

 contain pigmented or unpig-mented solid granules 

 of various sizes. 



The same nerve cells show also the presence of 

 many vacuoles, containing a transparent liquid. 

 These may be very abundant and are located 

 principally in the outer zone of the cytoplasm. 



The vacuoles represent granular deposits which 

 are in process of transformation, so as to furnish 

 energy for the work of the cells. 



Excessive work upon the part of the cells, 

 starvation, etc., serve to bring about the destruc- 

 tion of the granules, and their replacement by 

 vacuoles. The granules may, therefore, be con- 

 sidered to be storage material which may be called 

 upon at any time of special stress to furnish 

 energy for the work of the cells. 



Some OhservatioTis on the Behavior of the Beach 

 Flea, Orohestia agilis: A. M. Banta. (Intro- 

 duced by C. B. Davenport, Carnegie Institution, 

 Station for Experimental Evolution.) 

 When disturbed by lifting the eel grass the 

 animals are largely negative to light. In a few 

 minutes if prevented from concealing themselves 

 they become positive and remain so if the in- 

 tensity of light remains constant or is increased. 

 If the intensity is materially decreased, however, 

 the orchestias become negative. This is a most 

 exceptional reaction. With most organisms, if 

 there is a reversal of the light reaction with 

 change in intensity, the negative reaction is to 



