The Galea Capitis in llttnian Sperm 



169 



ing to the technique of Sjostrand (9, 10)) made it 

 possible to differentiate the two parts of the acro- 

 somal region and to follow the fate of these two 

 parts and of the cell membrane during the acrosomal 

 reaction. It also made possible the examination of 

 spermatozoa in contact with the egg surface. It has 

 been found that all spcrnuitozoa in contact with cgt^s 

 exhibit the acrosonuil reaction. The probable im- 

 portance of this phenomenon in fertilization is there- 

 fore emphasized. Spermatozoa treated with egg 

 water, on the other hand, do not show a full per- 

 centage of acrosomal reaction. 



Regarding the functions of the two parts of the 

 acrosome in the process of fertilization nothing in 

 the present observations is contrary to the belief 

 of Wada, Collier and Dan (II) that the acrosome 

 contains the lysin that dissolves the egg membrane, 

 although stages in this process could not be studied. 

 More likely the acrosomal globule is the one which 

 consists of and contains the egg membrane lysin. 

 The impression gained by Rothschild and Tyler (8) 

 from the electron microscopic study of whole mounts 

 (unsectioned material) that the acrosomal globule 

 forms the acrosomal filament seems to be erroneous. 



The author wishes to thank Dr. G. Gustafson, the 

 Kristincbcrg Zoological Station, and lk'st>rcr I). Riistai-I, 

 Trondhcim Biological Station, for the help and supply 

 of material; Dr. F. Sjostrand, Associate Professor of the 

 Dcpailnicnt of Anatomy, for placing the resources of 

 his laboratory at the author's disposal; F^rofessor J. 

 Runnstrom, the Wenncr-Gren Institute, for his unfailing 

 support and interest. Financial support from the Swedish 

 Natural Science Research Council is also gratefully 

 acknowledged. 



References 



1. Afzelius, B. K.,Z.ZeUforsch. 42, 134 (1955). 



2. Dan, J. C, Biol. Bull. 103, 54 (1952). 



3. — ibid. 107, 203 (1954). 



4. — ibid. 107, 335 (1954). 



5. Dan, J. C. and Wada, S. K., Biul. Bull. 109, 40 (1955). 



6. Fawcett, D. W. and Burgos, M. H., Ciba Foundation, 



Colloquia on Ageing 2, 86. London, 1956. 



7. Rhoimn, J., Correlation of Ultrastruclurai Organization 



and Function in Normal and Experimentally Changed 

 Proximal Convoluted Tubule Cells of the Mouse 

 Kidney. Stockholm, 1954. 



8. RoiHSCHiLD, Lord and TviiR, A., Exptl. Cell Rcsccinh, 



Suppl. 3, 304 (1955). 



9. Sjostrand, F. S., Nature, 168, 646 (1951). 



10. — /■// Osrru and Poi iistfr. Physical Techniques in 



Biological Research, 111, 241. New York, 1956. 



11. Wada, S. K., Collier, J. R., and Dan, J. C, E.xptl. Cell 



Research. 10, 168 (1956). 



The Structure of Galea Capitis in Human Sperm 



J. Schultz-Larsen and R. Hammen 



The University Institute of Human Genetics, the Department of Gynecology cmd Obstetrics at the 

 University Hospital, Copenhagen, and the University Institute of Biophysics, Copenhagen 



As galea capitis, at least as far as animals are con- 

 cerned, has shown itself to be important for sperm 

 fertility, we have undertaken an investigation of this 

 structure and its relationship to the acrosome as 

 part of our systematic electron microscopic research 

 on the normal morphology of the human sperm, in 

 the course of this work, we have found a formation 

 in the foremost part of the head of the sperm which 

 to our knowledge has not been described previously 

 in human sperm. 



Lively sperm from young men whose ejaculates had 

 been subjected to thorough analysis and found to be 

 normal were used. The ejaculates were diluted 10-15 

 times with Tyrode's solution, and fixed with 1 "o osmium 

 tetroxide with a pH of 7.4 in isotonic ion concentration. 

 Dehydration in alcohol and embedding in butylmetacry- 

 late. Our experiments have demonstrated that impurities, 

 which are present in large amounts in normal human 

 sperm, are largely the cause of irregular polymerisation. 

 When using chemical accelerators (bcnzoylperoxidc. 

 2:4,dichlorobenzoylperoxide, lauroylpcroxide)it has thus 

 been necessary to remove impurities from the ejaculates 

 prior to fixation by means of repeated centrifugation and 

 suspension in pure Tyrode solution. These procedures 

 have, however, proved to reduce the number of motile 

 sperm considerably, and the membrane mentioned above 

 is damaged. Polymerisation with ultra-violet light without 

 chemical accelerators makes it possible to work with less 



pure preparations and yet achieve satisfactory preserva- 

 tion. The sections have been cut with a Sjostrand ultra- 

 microtome with razor blades. In preparing sections with 

 the latter microtome, the method suggested by Sjostrand 

 (II) has been closely followed. 



In the preparations made by merely spreading a 

 suspension of sperm heads which had been subjected 

 to the normal cleansing and fixation procedures, one 

 usually cannot see the galea, and in no way gains any 

 impression of the structure to be described below. 



Fig. I shows that the galea is a hood-like structure 

 which reaches down o\er the forepart of the head. 

 The hood is in this preparation torn off the head. 

 The galea capitis consists of two layers; the inner 

 one, nearest to the head, and the outer layer, each 

 of which is about 50 A thick. The two lasers are 

 separated by a space appro.ximately 400 A wide. 

 The galea stretches from the foremost point of the 

 head down to the head's equator, where the inner 

 and outer layer form a cul de sac. Galea capitis is 

 bounded on its outer side by a thin membrane which 

 continues past the equator of the head to cover the 

 basal part. This outer membrane is only 50 A thick, 

 and its continuation forms the membrane that covers 

 the middle-piece, the tail and the tail tip. 



