Spindle and Cytoplasm 91 



tioii coinciding witli a jjhase contrast observation of Siredon erythro- 

 blastic prophase-metaphases made by the junior author (un- 

 published) . 



Root meristeniatic mitochondria tended toward constrictions and 

 fragmentations after exposures to colchicine for more than 25 hours 

 (0.005 M colchicine) (Fig. 3.9). Shorter exposures, 13 hours, were 

 less effective. The relation between viscosity and mitochondrial shapes 

 was believed valid.'^^ The mitochondria were demonstrated in Allium 

 (Fig. 3.9) in which cases mitochondria did not j^enetrate the 

 achromatic sphere (Fig. 3.9) (pseudospindle) about which the c-pairs 

 seemed to collect."^ 



While the Golgi bodies have not received the attention given other 

 cvtoplasmic organites,-^'^ fragmentation and scattering of these bodies 

 were induced in adult mice by 0.1 -mg. colchicine injections.^-^ 



Metabolic aspects of cytoplasm were demonstrated among tissue 

 cultures by differential staining with methylene blue (1:10,000). 

 The arrested mitoses remained colorless \\hile the cytoplasm of 

 resting cells was diffusely stained. Untreated cells in division are 

 also colorless because methylene blue is reduced more rapidly when 

 cells are dividing."'*' This suggests that arrested metaphase reduces 

 methylene blue like a regularly di\iding cell. This metabolic activity 

 mav provide an explanation for the e\entual destruction of arrested 

 mitoses in animal cells'"** (cf. Chapter 2) . 



"Bleb" formation occurred at cellular surfaces among grasshopper 

 neuroblasts-^'^ when mitosis was arrested. Also, notable cytoplasmic 

 agitations were seen among fibroblasts treated with colchicine and 

 studied by cinematographic projection. i" These observations call 

 attention to an unusual activity when cytoplasmic division is pre- 

 vented by colchicine. This agitation has been described by others 

 using treated tissue cultures.^^- '^^ Changes at cell surfaces can also 

 be induced by many other substances, such as mustard gas and ultra- 

 \iolet radiations. ■"'*• 



Some observed cases do not indicate direct action by colchicine. 

 The marine eggs of Psamynechiuus tniliaris obser\ed for birefringence 

 characteristics indicated that actions in the cortical layers were inde- 

 pendent of mitotic arrest."" Tubifex eggs pro\idcd additional cases 

 for observing the relation lietween changes in c\ toj)lasmic \ iscosity and 

 mitotic cycles.'''^ 



3.8: Reversible Characteristics of the Spindle 



L.et us summarize what has been detailed from Chapter 2 uj) to 

 this i>oint. If we compare a colchicine-mitosis (c-mitosis) with a 

 regular mitosis, our first impressions might well be the foll()^v•ing: 

 c-mitosis is mitosis without metaphase, anaphase, and telophase; 



