. The anatomical record. Anatomy; Anatomy. 378 ROBERT T. HAXCE point that staleness of tissue as well as improper technique may account for the great variation in the number of chromosomes reported for human material as it is very difficult to obtain this tissue in an absolutely fresh condition. It might also be sug- gested in view of the fact that all the mammals studied by me have over forty chromosomes that when a perfect fixation of human material is attained the number of chromosomes will be. 'IVxt H{i. 1 All foul- fi^;ur(>.s represent sperinntosoiiia of the \n^^ in iiietaphase. .1 anr
. The anatomical record. Anatomy; Anatomy. 378 ROBERT T. HAXCE point that staleness of tissue as well as improper technique may account for the great variation in the number of chromosomes reported for human material as it is very difficult to obtain this tissue in an absolutely fresh condition. It might also be sug- gested in view of the fact that all the mammals studied by me have over forty chromosomes that when a perfect fixation of human material is attained the number of chromosomes will be. 'IVxt H{i. 1 All foul- fi^;ur(>.s represent sperinntosoiiia of the \n^^ in iiietaphase. .1 anrl Ji illustrate the efTect of poor fixation on fresh tissue. The unequal size of the chroinosonies would seem to indicate that a fusion between various elements has taken plaee, and the massing togetherof these bodies in many cases make it impossible to distinguish the line of separation. Note that the chromo- somes tend to be globular in form and lack differentiation. (' and I) show the effect of the new method of fixation (innnediate iiuiiiersion in killing fluid) on stale tissue. C was taken from a testicle that had prt)ijably been removed from the animal for a longer i)eriod of time than had D. The large size and small numlwr of the chromosomes of T again suggest that a fusion Ix'tween chromosomes has taken i)lace. The stipled area is dense and very in- distinct. />) shows a cell in a slightly l)('t ter degree of preservation. The chro- mosomes are more numerous and better differentiated than in <'. 'VUv form compares more favorably with the morphology of the ciironuisoiiies found in properly i)reserved material. In I) there is consideral)le density and lack of distinctness in the center of the chromosome plate indicated in the drawing liy the stipled portion. Compare these drawings with figures 1, 2. 'A, 4 and Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearan
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomy, bookyear1906
