-^34 Journal of Applied Microscopy 



entiation was obtained by double staining with haematoxylin and orange G. 

 Cell boundaries were clearly defined by double staining in haematoxylin and 

 alum carmine. Total preparations for control of sectioned material were made 

 by dissecting out the eggs from the worms, fixing in picro-acetic, washing out 

 in alcohol, and then staining in a mixture of pure glycerine and enough acetic 

 carmine to give a pale rosy tint to the mixture. In 1 to 2 days the eggs become 

 very transparent and give splendid optical sections in any desired plane when 

 mounted under covers on hairs for rollers. This stain is not permanent. 



For the study of development after the hatching that normally takes place in the 

 intestine or faeces of the frog, the method of Leuckart was used, but in modified 

 form to insure pure cultures. The culture medium, a mixture of intestinal con- 

 tents and earth, was first sterilized by heat and then planted with embryos which 

 were removed from the parent by dissection. c. a, k. 



GENERAL PHYSIOLOGY. 



RAYMOND PEARL, University of Michigan. 



Books and Papers for Review should be Sent to Raymond Pearl, Zoological Laboratory, 

 University of Michigan, Ann Arbor, Mich. 



Stade, W. Untersuchungen iiber das fett- In the course of this study of the fat 



spaltende Ferment des Magens. Beitr. z. splitting enzyme of the stomach, steap- 

 chem. Physiol, u. Path. 3: 291-321, 1902. r & / ^ t- 



sin, the author discovered a new and 



interesting law of ferment action. The method of experimentation followed was 

 to add to a definite amount of fresh gastric juice a known quantity of egg yolk. 

 Portions of the yolk were removed after digestion had proceeded for definite 

 periods of time, and the amount of fatty acid which had been split off determined 

 by analysis. It was found that the percentage of fatty acid formed after differ- 

 ent times of digestion were very nearly equal to the square roots of the times of 

 digestion. This relation is shown by the following results from a single series 

 of experiments: 



1.95 2.8 3.4 3.8 48 6.85 per cent, of fatty acid 



after 3 6 9 12 24 48 hours digestion. 



The square roots of the times of digestion are 



1-7 2.5 3.0 3.5 4.9 6.9 



The agreement is seen to be very close. This law may be generalized in the 

 following formula : 



P ■ P\ '• Pi ^ \ ^ • 1 ^1 -1 '^2' '" which / stands for percentage of 

 product formed and / for time of digestion. r. p. 



Seligman, C. Q. On the Physiological Action The Kenyah dart poison is prepared by 



of the Kenyah Dart Poison Ipoh, and its the natives by heating the sap of the 

 Active Principle Antiarin. Jour. Physiol. ... . . 



29: ^9-57,190-'. upas tree, Antians toxiair/a. Alter 



heating the sap slowly solidifies into a 

 hard, black resinoid mass, which is almost entirely soluble in water. This sub- 



