Februakt 14, 1913] 



SCIENCE 



269 



the responses are, in general, like those involved in 

 taking food. The distinctive feature of the second 

 condition (negative) is a bending of the tentacle 

 at the point stimulated but away from the stim- 

 ulated side. The positive and negative conditions 

 are not necessarily correlated with hunger and 

 satiety, nor with the state of the medium in which 

 the animal lives, nor with fatigue. While external 

 conditions remain as nearly as possible constant, 

 the animal may abruptly change back and forth 

 from one condition to another. The reactions, 

 therefore, while influenced by external conditions, 

 depend essentially upon an internal physiological 

 complex. 



A. J. GOLDFARB (College of City of New York) : 

 On the Effects of Changes in Density of Sea 

 Water upon Growth and Regeneration. 

 G. H. Paeker and E. M. Stabler (Harvard Uni- 

 versity) : Taste, Smell and Allied Senses. 

 The statement that the stimulus for smell is 

 material in the form of gas and for taste is 

 material in solution is partially incorrect, for 

 both sense organs are normally stimulated by 

 solutions. It has been recently shown that fishes 

 respond to their food by smell and taste much as 

 air-breathing vertebrates do. What seems to be 

 the chief difference between smell and taste is 

 that the olfactory organs are stimulated by very 

 dilute solutions, the organs of taste only by much 

 stronger ones. To get some quantitative statement 

 of this difference, the strength of the stimulating 

 solution producing the minimum stimulus was 

 determined for a substance that had both smell 

 and taste. The substance tested was ethyl alcohol. 

 In preliminary tests the following results were 

 obtained. The weakest dilution that would stim- 

 ulate the mucous surfaces of the mouth was a 

 15 mol. solution (aqueous). The weakest dilution 

 that called forth the sweet taste when applied to 

 the tongue was a 2 mol. solution (aqueous). The 

 weakest dilution that could be smelled was 

 1/200,000 mol. (in air). Thus the olfactory ap- 

 paratus responds to a dilution about 400,000 times 

 greater than that for taste. 



G. G. Scott (College of City of New York) : The 

 Effect of Fresh Water upon Fundulus hetero- 

 clitus. 



It is now well established that Fundulus hetero- 

 olitus is found in both sea water and fresh water. 

 The fact that few survive rapid transference from 

 salt to fresh water while greater numbers survive 

 gradual transference shows that we are here con- 

 cerned with another application of DuBois Eey- 



mond's law of stimulation. Out of a lot of ten 

 F. heteroclitus transferred from salt to fresh 

 water, the present author kept one fish alive in 

 fresh water for sixty days. When the caudal fin 

 is removed at the time the fishes are transferred 

 from salt to fresh water regeneration of new 

 caudal fin tissue takes place, although in a month 's 

 time the amount is not as great as in sea water. 

 Of greater interest from the point of view of the 

 mechanism of adaptation are the results of experi- 

 ments in which individual records were kept of 

 changes in weight made at a number of intervals 

 after immersion of Fundulus in fresh water. In 

 some cases all members of a lot of fishes died soon 

 after transfer. In each case a rapid increase in 

 weight was noted. In other cases certain indi- 

 viduals gain weight rapidly and die. Other indi- 

 viduals of the lot after an initial gain in weight 

 follow this with slight gains and losses — the net 

 results in these survivors being a weight less than 

 normal at the end of the experiment. The experi- 

 ment apparently illustrates the power of Fundulus 

 heteroclitus to change the organization of the 

 limiting membranes and other structures of the 

 body to the end that the fish becomes adapted to 

 fresh water, a medium of very low osmotic pres- 

 sure as compared with sea water. 

 Max Morse (Trinity College) : Factors Involved 



in the Metamorphosis of Amphibia. 

 A. G. Mayee (Carnegie Institution) : The Vital 

 Limits of Seef Corals in Respect to Tempera- 

 ture. 

 S. O. Mast (Johns Hopkins University) : Thir- 

 teen Hundred Generations in Didinium without 

 Conjugation. 



A. J. GOLDFARB (College of City of New York) : 

 On a New Method of Grafting Embryos in 

 Large N timbers. 



EMBRYOLOGY AND DEVELOPMENT, CYTOLOGY 



Albert Kuntz (University of Iowa) : The Histo- 

 genesis of the Cranial Sympathetic Ganglion in 

 the Pig. 



H. L. Clark (Harvard University) : Ontogenetic 

 and Localized Stages in Ophiurans. 



C. M. Child (Uiaiversity of Chicago) : Senescence 

 and Mejuvenescence in Flanaria velata. 



B. M. Allen (University of Wisconsin) : Some 

 Methods of Embryological Technique. (Accom- 

 panied by a demonstration.) 



Charles Zelbny (University of Illinois) : Experi- 

 ments on the Control of Asymmetry in Young 

 Serpulids. 



