and Laboratory Methods. 1221 



of the infusorial! becomes rounded and uneven in contour, and there is a ten- 

 dency, as the concentration approaches the maximal point, for the chromatophores 

 or amylum bodies to join together and form large masses. 



A method is described for making pure cultures of infusoria. A culture fluid 

 is prepared according to the following formula : 



Meat extract 1 gram. 



Cane sugar 20 grams. 



" Concentrated, cooked infusion of Porphyi'a vulgaris " . 250 c. cm. 



Distilled water 729 c. cm. 



This culture fluid is sterilized and the desired infusoria are introduced into 

 it by means of a capillary tube. The capillary tube can be examined under the 

 microscope, and only that part of it which contains the species wanted is emptied 

 into the culture fluid. The medium is thus inoculated with a single species and 

 by multiplication a pure culture results. This method is stated to be very suc- 

 cessful in practice. R. p. 



Moore, A. Further Evidence of the Poisonous The purpose of this work is to deter- 

 Eff ects of a Pure NaCl Solution. Amer. jj^j^e whether pure solutions of various 

 Jour. Physiol. 4 : 386-396,1900. 



electrolytes have the same poisonous 



effects on fresh water animals as they have been shown to have on those living 

 in sea water. The organisms used were young trout, and frog tadpoles. The 

 trout were taken just after hatching and immersed in solutions of known concen- 

 trations. The time of death as indicated by the cessation of respiration was 

 noted and the results from different combinations of salts were tabulated. The 

 results are entirely confirmatory of Loeb's work on other forms. It was found 

 that pure solutions of the chlorides of Na, Ca, K, Mg and Li were poisonous. 

 The poisonous effects of NaCl were antagonized by Ca, but the latter was not 

 found, however, to be in itself necessary, since it made a sugar solution more 

 harmful. K did not counteract the effects of Na, but was antagonistic to Ca 

 used in small quantities. Sugar in weak solutions was as poisonous as NaCl in 

 solutions of equal osmotic pressure, while in stronger solutions it was less pois- 

 onous. The solutions in which the animals lived longest were combinations of 

 NaCl and CaCl2, or of these two salts with the addition of KCl. The young 

 trout lived indefinitely in distilled water, showing that no salts are directly neces- 

 sary for the preservation of life. A point of interest was that in case of the trout 

 the heart beat continued for some time after respiration had ceased. Many of 

 the solutions caused a remarkable shrinkage in the volume of the frog tadpoles 

 kept in them. R. p. 



Galloway, T. W. Studies on the Cause of the It is known that an increase of temper- 

 Accelerating Effect of Heat upon Growth. ^^^^^ causes an increased rate of growth 

 Amer. Nat. 34 : 949-957, 1900. . . ° 



in many organisms. The purpose of 



this paper is to determine whether in accelerated growth due to increase of tem- 

 perature, the imbibition of water and the anabolic metabolism are equally accel- 

 erated, and, if not, which of the two processes is more accelerated. Larvae of 

 Rana sylvestris, Amblystoma puiictatmn and Bufo america?ia were used in the 

 experiments. Fertilized eggs were subjected to three different temperature con- 



