294 The Philippine Journal of Science im 



some cases of intestinal amoebiasis that are refractory to other 

 forms of treatment do respond to treatment with salvarsan. 



The paper included a citation of the more important literature 

 on intestinal spirochsetes. The authors do not take up the 

 systematic position of the spirochsete seen by them, nor do they 

 attempt at this time to establish its identity with Spirochsetd 

 eurygyrata Werner, emend. Fatham. The paper was accom- 

 panied by the demonstration of stained preparations of the 

 spirochsetes by the haematoxylin and Benian's methods. 



DEMONSTRATION OF OSSIFICATION CENTERS IN THE HUMAN 



EMBRYO 



By Dr. Edward S. Ruth 



The method for demonstrating the formation and ossification 

 centers of bones was first described by Schultze. Human em- 

 bryos up to the sixth and seventh month of intrauterine develop- 

 ment may be used for the demonstration of bone formation. The 

 embryo is first placed in 95 per cent and later in absolute alcohol 

 until the soft parts have all shriveled. The specimen is then 

 placed in a 1 per cent solution of potassium hydroxide until the 

 soft tissues are transparent and the calcareous matter can be 

 distinctly seen. Formalin-hardened specimens may be also 

 cleared in this manner, providing a stronger solution of potas- 

 sium hydroxide is used, up to 10 per cent. After the embryo 

 is fairly transparent, it is placed in a solution consisting of 

 water, 20 parts; glycerol, 20 parts; and strong ammonia water, 

 30 parts. In this solution it can be left indefinitely, until the 

 specimen is perfectly clear. For permanent mounting it may 

 be placed in glycerol or it may be prepared according to the 

 Bardeen method, that is, splitting the embryo in the saggital 

 plane and mounting it on a glass plate covered with gelatin; 

 this is then placed in a solution of glycerol, which hardens the 

 gelatin by dehydration and fixes the specimen to the glass plate. 



A number of human, pig, and duck embryos, which were pre- 

 pared by the above method, were demonstrated. The human 

 embryos varied from 2 months and 1 week to 4 months and 3 

 weeks of age. 



ACIDOSIS AND THE DETERMINATION OF THE CARBON DIOXIDE 



OF THE ALVEOLAR AIR 



By Dr. R. B. Gibson 



The , various recently proposed methods ^ for determining the 

 alkaline reserve of the body were discussed, in particular the 



' Marriott, Van Slyke, and others. 



