830 SEC. 18. BIOLOGY. 



3839b. Preparations on the Embryology of the Sterlet 



(Acipenser ruthenus). 



The time is fixed approximately, as at an early stage temperature and 

 quantity of food have a great influence on the development. No. 1 . First day, 

 the hole of Rusconii forms the half of the egg. No. 2. Second day, morning, 

 the hole of Rusconii is smaller. No. 3. Second day, evening, the hole of 

 Rusconii is very small. No. 4. Fourth day, the hole of Rusconii has dis- 

 appeared. No. 5. Fifth day. No. 6. Sixth day. No. 7. Seventh day. No. 8. 

 The third and fifth days after their coming out from the egg. No. 9. About 

 a week after their coming out. Nos. 10, 11, 12, 13. From two to four weeks. 

 No. 14. About six weeks ; bastard of an Acipenser Giildenstaedtii (soft roe), 

 and of an Acipenser ruthenus (hard roe). No. 15. About two months. 

 No. 16. About a year ; reared in an aquarium. If there is plenty of food the 

 fish can attain about double this size in the same period. 



3840. Original Cast of the trunk of a boy, the thorax opened 

 to show the natural position of the heart after removing the lungs. 



Steger and Honikel, Anatomical Institute, Leipzig. 



3841. Cast, with the Abdominal Cavity opened to show 

 the natural form and position of the stomach, liver, and kidneys, &c. 



Steger and Honikel, Anatomical Institute, Leipzig. 



3842. Several Small Original Casts. 



Steger and ffonikel, Anatomical Instate, Leipzig. 



3843. Histological Photographs. 



Steger and Honikel, Anatomical Institute, Leipzig. 



3844. Photographs to illustrate the Changes during De- 

 velopment. 



Steger and Honikel, Anatomical Institute, Leipzig. 



3845. 25 Photographs on Glass, for the magic lantern, 

 for instruction in physiology (anatomy, physiology, biology, and 

 development). Dr. S. Th. Stein, Frankfort. 



These slides have been photographed from nature. - 



3846. Three Large Diagrams. Dr. S. Th. Stein, Frankfort. 



These contain 



1. 35 physiological photographs. 



2. The application of photography to physiology and medicine. 



3. Thermophotography. (The whole taken from nature.) 



3847. Diagrams, for botanical teaching, by L. Kny. 

 1-20. Prof. Kny, Berlin. 



These diagrams are published by Wigand, Kempel, & Co., Berlin. 



3848. Collections, for botanical teaching (in portfolio). 



Prof. Kny, Berlin. 



3849. Model of the Mechanism of the Accommodation 

 of the Eye. Prof. Beetz, Munich. 



This model is made from a design of Dr. Beetz, and is explained by a 

 drawing and description which accompany the apparatus. 



