A MARINE irNIVf:KSITY, ' 631 



unfertilized egg-sof 'Arl)aQi((, a sea-urchin, when treated with sohition.s 

 of .sodium and magnesium chlorides, would 8egn)ent and advanc(> into 

 much later stages than those observed by Hertwig, though no swim- 

 ming emljryos were produced. Thus to Morgan and Lo(^l), of Woods 

 Hole, belong a large share of the credit of what has been called one of 

 the most epoch-making disco\eries of modern times, that of artiticial 

 fertilization. 



Parthenogenesis, or the development of a female eg^ without the 

 access of a male element or spermatozoon, had long been known 

 among various lower types of animals; instances are to be found in 

 the bees, social wasps, ^c>yy/(6y,/'^>.syc7/r, Daphnia, plant lice, and others. 

 Here was a case of artiticial parthenogenesis, and Loeb was led to 

 compare these natural and artiticial phenomena, reaching the conclu- 

 sion that fertilization carries into the o^gg a catalytic substance which 

 accelerates a process which would otherwise proceed too slowly. Thus 

 fertilization, from having a purely vital aspect, assumes a chemico- 

 physical aspect, and the hitherto mysterious phenomena of i)artheno- 

 genesis finds a partial explanation. 



In his discussion of this development without the male element, 

 Loeb says it has !in important l)earing upon the theory of life 

 phenomena: 



If we siUTeeil in tindinii a sul)staiice w hifli aceelerak's thr process of cell (Uviyion 

 at the normal temperature, this will at the same time lead to a suppression or reduc- 

 tion of the antagonistic process that shortens life. It is not impossible that " natural 

 death" is comparable to the situation on the mature ej^g after it leaves the ovary. 

 Nature has shown us the way by whicli at this critical point death can he avoided 

 in the case of the egg. 



It is safe to j)r()phcsy tiiat the ))earing of these and similar discov- 

 eries on medicine and pathology will l)e no less important than the 

 experiments of Pasteur on ])acteria. 



The eti'ects of ditferent solutions upon the development of the egg is 

 illustrated l)y an experiment conducted l)v nature herself: BninvluppuH 

 stcK/iuiUs is a fi'esh-water crustacean, which, if raised in concentrated 

 salt solutions (salt lakes), becomes smaller, undergoes some other 

 changes, and transforms into a species Avhich has l)een known as 

 Artein!(( SI// /'//(/, -a classic case of transformation under the action of 

 external conditions, tirst observed by Schmankewitsch. This observer 

 kept Art<'iiu<i \v. salt water, which \\q constantly diluted by adding 

 fresh water until at last it was perfectly fresh; the ciiistaceans had 

 meanwhile gon<' through several generations, and had gradually so 

 completely changed tlunr characters that tinally they accpiired those of 

 the genus BranehipjxtH. 



The artiticial pr()c(\ss has be(m errou(H)usly spoken of in the press as 

 "chemical '''' fcrtdization. The single fact that Dr. Albert Mathews has 

 been able to initiate development by the shaking of the (\'^)^ indicates 



