1 88 SIGNIFICANCE OF MALFORMATIONS IN ORGANOGRAPHY 



I may only say further that if Basidiobolus be cultivated in a i/ solution 

 of ammonium-sulphate or a i/ solution of ammonium-chloride it may 

 be induced to form a ' palmella-stage ' such as is known in no other 

 fungus it breaks up into spherical cells with thick walls, and these are 

 then set free from the old cell-envelope. In this case the arrest of the 

 development is apparently not so far-reaching as it is when the giant-cells 

 are produced. 



We meet with similar phenomena in some Algae. In them the 

 nature of the nutrient solution, especially its concentration, will call forth 

 malformations although these are not so extensive as they are in Basi- 

 diobolus. Thus Chodat and Huber 1 found that the formation of 

 daughter-colonies was suppressed in Pediastrum Boryanum, when it was 

 grown in concentrated nutrient solutions, and the cells sometimes became 

 large ' hypnocysts.' Richter 2 produced similar abnormalities by culti- 

 vating other freshwater algae in salt solutions. 



Passing now to the Spermaphyta, I must in the first instance quote 

 the words with which Peyritsch, one of the most fertile investigators in 

 the domain of the causes of malformations, introduces his treatise upon 

 the etiology of the formation of peloria 3 : 'In the investigation of the 

 etiology of peloria, and generally of deviations in construction from the 

 normal, there are two factors which must not be lost sight of; one is 

 the immediate determining cause, which in many cases may be an external 

 agent, and the other is an internal factor, namely, the predisposition to 

 the development of the anomaly. It is easy to convince oneself that all 

 the individuals of the same species do not react in the same way towards 

 the same external injurious agencies, and that their reaction also varies 

 at different times. The capacity to change, to appear in abnormal forms, 

 to become diseased, does not exist in all of them in the same way.' 

 This is a conclusion to which the researches of de Vries above referred 

 to also lead. It is not however to be regarded as applicable solely to 

 cases of malformations, it holds for the operation of all external factors 

 upon relationships of configuration., and in malformations we have merely 

 the evidence of predispositions which do not normally show themselves. 

 Whether we are to consider peloria as malformations or as reversions is 

 of no moment for our question here. No doubt these wonderful forms of 

 flower exhibit a more primitive type than the dorsiventral flowers which 

 are the normal ones in the plants in which they occur. 



With regard to the etiology of peloria, it is known that if terminal 

 flowers are produced upon shoots which otherwise have only dorsiven- 



1 Chodat et Huber, Recherches experimentales sur le Pediastrum Boryanum, in Bull, de la 

 societe hot. Suisse, 1895. 



- Richter, Uber die Anpassung der Siisswasseralgen an Kochsalzlbsung, in Flora, Ixxviii (1892), p. 4. 

 ' 1'eyritsch, in Denkschriften der Wiener Akad. d. Wissensch. xxxviii (1878). 



