576 
C. F. U. MEEK. 
In 1909 Gallardo replied to these criticisms. He withdrew 
his qualification in the case of chromosomeless spindles; and, 
instead, denied that they can be formed, affirming that their 
appearance is an illusion produced by juxtaposition of rays of 
two centrosomes lying close together. He saw no reason for 
regarding as chromosomeless the spindles in Baltzer’s early 
stage triaster, and believed that these were formed in the 
normal manner and in accordance with his theory. 
Dui’ing the same year Hartog also published a reply to 
Baltzer’s criticisms. Again postulating the dual character of 
the mitotic force, which Avas said to resemble electrostatic 
force or magnetism, he repeated that the centrosomes are 
unlike poles, and said that magnetic experiments suffice to 
remove Baltzer’s objections. He pointed out that a triaster 
can be produced with a neutral iron core and two unlike 
magnetic poles, and that three charcoal iron balls, placed in 
a magnetic dust-field traversed by an electric current, behave 
as three equal and equidistant centi*es united by spindles. 
Furthermore, he showed that tetrasters having one diagonal 
spindle can be obtained with two unlike magnetic poles 
alternating with iron cores, and denied the existence of 
tetrasters with two diagonal spindles, as shown by Baltzer. 
In the following year he said that Gallardo’s theory is dis- 
proved, because cases are known in which full-grown spindles 
have been formed in the absence of chromatin, and agreed 
with Baltzer that in the animal cell the spindle is ahvays at 
first chromosomeless. Since no spindle can be formed between 
like poles, and since the mitotic spindle appears to be homo- 
polar with respect to all known forces, he concluded that mito- 
kinetism is a new force unknown so far outside the living cell. 
The views of Gallardo and Hartog were criticised by 
Baltzer in 1911. He pointed out that the denial of the 
existence of chromosomeless spindles is refuted by his figures 
and those given by Wilson in 1901 ; for in these the asters 
are too far apart to permit the explanation of juxtaposition : 
moreover, in Gallardo’s figure explaining the early stage of 
the triaster, the lines of force ai-e bent at the equator; and. 
