472 



SCIENCE 



[N. S. Vol. XLI. No. 1056 



Local reactions were obtained in response to me- 

 chanical and chemical stimulation, the order of 

 decreasing sensitivity of the parts of the- animal 

 being: proboscis, posterior end, genital pleuraa, 

 the alkaline metals the normal lyotropic series, 

 abdominal surface, collar. For the chlorides of 

 K > NHj > Li > Na, wag found to express their 

 stimulating efficiency; this was mainly a kation 

 stimulation, but in the case of salts (CaCL, e. g.,) 

 which did not stimulate strongly, other anions (in 

 this case Ca(NOs).) were effective as stimulating 

 agents. Photic sensitivity was readily separated, 

 by exhaustion or anaesthetics, from mechanical and 

 chemical; but for the two latter forms of irrita- 

 bility no physiological separation was discover- 

 able. It is therefore suggested that in Ptychodera 

 there are generalized receptors open to stimulation 

 by both mechanical and chemical means. 



On a Certain Fibrin Beaction Which Occurs in 

 Living Cultures of Frog Tissues: Geoege A. 

 Baitsell. 



In living cultures of various tissues of the adult 

 frog there occurs, in many instances, a transfor- 

 mation of the fibrin net of the plasma clot in 

 which the living tissue is embedded. In general 

 the changes which occur first make their appear- 

 ance when the culture is from two to three days 

 old. During these changes the elements of the 

 fibrin net appear to fuse or consolidate and as a 

 result there are formed a great number of fine 

 wavy fibrils which unite to form bundles of fibers, 

 and these freely intertwine and anastomose as 

 they ramify throughout the area of the plasma 

 clot. The transformation of the fibrin net begins 

 first in the region of the clot which lies in immedi- 

 ate contact with the embedded tissue and gradu- 

 ally extends to the distal regions of the clot until 

 after a time practically the entire plasma clot be- 

 comes changed into a tissue greatly resembling 

 that found in various types of connective tissues. 

 Photographs of both living and preserved cultures 

 have been made to show the transformation of the 

 clot and the development of the fibers. Experi- 

 mental work shows definitely that the fibers arise 

 by a transformation of the fibrin net and are not 

 due to any intracellular action. The work also 

 indicates that the transformation will not take 

 place without the influence of living tissues, al- 

 though mechanical factors may be introduced 

 which will aid in the formation of the fibers. 

 Various experiments made to determine the true 

 nature of the fibers give conflicting results. The 

 fact, however, that the fibers have also been found 



to occur in the fibrin net during wound healing 

 indicates that they play an important part in such 

 a process. Studied histologically with a Mallory 

 stain, there appears to be nothing to differentiate 

 them from regular connective tissue fibers. Work 

 is in progress to determine their final fate and the 

 relation they bear to permanent connective tissue 



Studies on the Phosphorescent Substance of the 



Fire-fly: E. Newton Hakvet. 



Dried powdered luminous tissue of the fire-fly 

 will phosphoresce strongly if moistened with water 

 containing oxygen. If first extracted with boiling 

 ether or a mixture of equal parts boiling ether 

 and alcohol for eight hours and the solvent then 

 removed, strong phosphorescence still occurs when 

 water containing oxygen is added to the dry 

 powder residue. Similar results are obtained with 

 hot chloroform and acetone, and cold carbon tetra- 

 chloride and toluol. 



If oxygen-free water is added to the dry 

 powdered luminous tissue no phosphorescence 

 occurs. If oxygen is then added light is emitted. 

 But if no oxygen be admitted until an hour or 

 more after contact of the powder with oxygen- 

 free water, then phosphorescence does not occur. 

 Salt, acid and alkaline solutions give similar re- 

 sults. 



From these experiments we may conclude: (1) 

 that the photogenic material is not a fat or a 

 lecithin; (2) that the photogen or some accessory 

 substance is unstable and decomposes in the pres- 

 ence of aqueous solvents even though oxygen be 

 absent. The change is therefore not oxidative in 

 nature. It is well known that the photogen oxi- 

 dizes readily in presence of oxygen and is used up 

 with light production. 



Dried luminous bacteria give similar results, 

 with this exception, that extraction with chloro- 

 form, acetone and a mixture of equal parts boil- 

 ing alcohol and ether destroys or weakens the 

 powder to phosphorescence. The bacterial photo- 

 gen is also unstable if the bacterial cell is broken 

 up in the absence of oxygen. 



Some Experiments on Fundulus Eggs Aiming at 

 the Control of Monstrous Development : E. J. 

 Webber. 



Starting from the assumption that human and 

 other mammalian monsters found in nature may be 

 due to a pre-uterine or intra-uterine poisoning by 

 the substances found in the blood under patholog- 

 ical conditions of metabolism, such as diabetes, 

 nephritis, jaundice, etc., eggs of FundvXus hetero- 



