190 FREDERICK G. E. PAUTARD 



Stentor coeruleus, and Spirostomum ambiguum, and the flagella from 

 unicellular algae (such as Polytoma uvella, Polytomella caeca, and 

 Chlorogonium elongatum, which can be grown under controlled and 

 sterile conditions to yield useful quantities of flagella) could not be 

 separated clearly from the cells without rupture of the cell wall and 

 extrusion of cytoplasm. 



Spermatozoa appeared to be the remaining subjects most likely to 

 provide pure preparations of flagella, but most of these were rejected 

 either because the flagellum was too complex to provide a fraction re- 

 liably identifiable as the "9 plus 2" system, or because the supply was 

 erratic. Fish sperm were by far the most profitable source of flagella, 

 but of those considered, only two fresh- water fish, the brown trout 

 (Salmo fario) and the perch (Perca fluviatilis), were available locally 

 and in sufficiently large quantities to permit adequate study. The 

 sperm from these two fish (Fig. 1) have the great advantages of sim- 

 plicity and length of flagellum, apparent absence of a midpiece and 

 other mitochondrial apparatus, comparatively reliable separation of 

 tails from heads, and high yield of flagellar substance. An average 

 preparation of 100 rag of dry flagella was obtained from fifty ripe 

 trout, but unfortunately this otherwise ideal source of flagella was 

 limited by the shortness of the spawning season, so that research, at 

 least on fresh material, was confined to about three months of the year. 



EXPERIMENTAL PROCEDURE 



The culture of the unicellular algae Polytoma uvella, Polytomella 

 caeca, and Chlorogonium elongatum and the separation of flagella 

 have been described elsewhere (Pautard, 1958a) and will not be con- 

 sidered here. 



Fish sperm were obtained from a number of sources. Small supplies 

 of cod (Gadus morrhua) sperm, removed from whole chilled testes, 

 were sent from the Torry Research Station, Aberdeen, and similar 

 quantities of cooled herring (Clupea harengus) sperm were supplied 

 from the White Fish Authority laboratory at Lowestoft. Fresh-water 

 fish, the main source of spermatozoa, were either kept in tanks until re- 

 quired or the milt was dispatched in sealed bottles from a local supply. 

 During the latter part of April and early May, quantities of ripe male 

 perch were supplied by the Biological Research Station, Lake Winder- 



