Abstract
1) Two types of Chironomus (chiefly Chiromomus dorsalis Meigen, and as reference Chironomus sp.) were examined by the usual acetocarmine method and also under acid-vapour treatment.
2) The longitudinal threads in the chromosome ought not to be regarded as chromatic interfaces between vacuoles as Metz and his coworkers insist upon. They ought to be regarded as continuous chromonema (single or multiple), with chromatic granules on it.
3) The synapsed chromosome consists of two cylinders twisting, as has already been recognized by many authors. The mode of twisting of two partners has been scrutinized in chromosomes I and IV. It has been demonstrated that a synapsed chromosome is like a rope where two partners twist around each other to right or to left, changing often the direction and the amplitude of twisting.
4) The shape of the transverse section of the synapsed chromosome, is usually circular and often becomes elliptical but never tape-shaped.
5) Constrictions of chromosome are explained by the lateral pressure produced by the tortion of the chromosome and by two other factors.
6) Cross striations appear sometimes to be a spiral state, but they are explained always as discs.
7) Cross striations are produced by the coalescing of the chromomere of the same rank. The older the chromomere is the more advanced is the degree of the coalescing.
8) Images produced by the vapour treatment of the acetic acid correspond well. if the acid is not concentrated. to the imagines of acetocarmine preparations.
9) Images of carmine preparaiton correspond well to the natural images in their gross appearance, although many cross striations or a part of the cross striation is not natural in their finer details. This is clearly shown by the acid-vapour treatment under the microscope (as, for example, when chromomeres coalesce transversely or sometimes longitudinally). The artefacts of this sort may not prevent the argument of the gene loci as done by many authors of the genetic line.
10) With acid vapour treatment, cross striations become sometimes heterogeneous i.e. they become in one part distinct and in another part indistinct. Two cross striations unite sometimes completely to one cross striation.
