ZOOLOOY AND BOTANY, MICROSCOPY, ETC. 837 



similar effect, (^d) ('hiuium sulfuricum in 0*05 ]y(ii' cent, solution acting for 

 20-30 minutes caused retrogression of the plasma radiation, and tins was 

 restored after immersion for a longer jieriod. In 5 minutes the amj)liiaster 

 underwent a retrogressive segmentation. Preserved material showed that 

 an action of 20 minutes sufficed to prevent or destroy nuclear fission, 

 (e) Chloral; in eggs treated with 0*5 per cent. S(dut!ou for 15 minutes the 

 radiation disappeared, and in 30-60 minutes small projections aj^peai-ed on 

 the surface. After bh hours the ova lost their susceptibility to impregna- 

 tion. (/) Cocain acted like chloral and chinium sulfuricum. 



(5) Kesults of thermic action on the products of reproduction. (1) Eggs 

 kept in sea water at a temperature of 31° C. («) 10 minutes ; penetration 

 of spermatozoa abnormal and incomplete : after 1{ hours no copulation of 

 nuclei took place. (6) 20 minutes ; greater part of the ova fertilized by 

 two to three spermatozoa. In 2^ hours segmentation began ; somewhat 

 impaired, (c) 45 minutes; fertilization, usually by three to four spermatozoa, 

 sometimes by five, rarely by two (15 ova — 56 sperms), (d) 60 minutes; 

 fertilization by three to five spermatozoa, rarely by seven or eight : no 

 segmentation observed, (e) 90 minutes ; fertilization by three to four 

 spermatozoa : no reaction of the female plasma. (2) Ova heated to 55° C. 

 for 5 minutes were killed, drops of albumen separating out. (3) Heated 

 to 50°, 47°, 45°, 42°, 41' C. for 5 minutes, no fertilization. (4) Heated to 

 39°, 37°, 36° C., fertilization took place, no segmentation. (5) Heated to 

 34°, 32°, 31° C, for 5 minutes, fertilization and segmentation with sub- 

 sequent "monster" formation. 



(6) Eifect of mechanical injuries. Ova shaken up in a test-tube half 

 filled with sea water for 20-30 minutes. The gelatinous membrane separated 

 from the yolk-sac. The otherwise undamaged ova were as a rule fertilized 

 by one spermatozoon. Ruptured ova may be impregnated by several 

 spermatozoa. 



(7) Preservation. Eggs were killed in picro-acetic acid, carefully washed, 

 and put in 75 per cent, spirit. Staining with lithium carmine or Gren- 

 acher's borax carmine (24 hours, extraction with 75 per cent, spirit 

 acidulated with 1/2-1 per cent, hydrochloric acid). Finally absolute 

 alcohol ; then mixture of equal parts absolute alcohol and oil of cloves ; 

 evaporation of the alcohol (best under a bell-jar and with vessel filled with 

 strong sulphuric acid close by) dammar or glycerin. Gradual transference 

 from one reagent to another brought out the nuclear figures more clearly 

 than when those operations were quickly performed. 



Preparing Tendon-cells and Cells of the loose Subcutaneous Tissue.* — 

 Dr. A. Dogiel obtained very good preparations of tendon by placing rat's 

 tail in Grenacher's alum-carmine for two or three hours, or still better, for 

 a week or even a month. The tendon bundles swell up and become trans- 

 parent, and the cells ai:>pear beautifully stained. The elastic fibres stand 

 out very clearly. The same efiect may be obtained if tendon be placed in 

 a saturated solution of potash or ammonia alum, and afterwards staininc' 

 with Grenacher's carmine, alum logwood, haematoxylin, eosin, &c. Mounted 

 in glycerin, the preparations keep for a long time, but afterwards a slight 

 decoloration takes placa. Permanent preparations of tendon are better 

 placed in spirit, then oil of cloves, wherein they are teased out, then 

 dammar or balsam. For the subcutaneous tissue it is recommended to take 

 a piece free from fat from the inguinal or abdominal region of a mammal, 

 and having spread it out, to stain with a concentrated solution of fuchsin, 

 diluted with an equal volume of water, and then stain under the cover- 



* Aiiat. Auzeig., ii. (1887) pp. 139-42. 



