i«94- NOTES AND COMMENTS. 3 



change of the conditions anywhere throws the whole system out of 

 gear, and when it settles again into a new position of equilibrium, 

 everything will be slightly altered, some things much altered. 

 Similarly, the body of every organism is in equilibrium and changes 

 of any part are reflected over every part. The method of change 

 favoured by Dr. Pfeffer is change of function. Changes of species, he 

 says, occur by reason of the change of function of the species in 

 question. 



The difficulty about these, and many similar pamphlets in English 

 and in German, is that they contain much shrewd criticism and in- 

 genious suggestion, coupled with a complete failure to understand the 

 difficulties of the general questions they lightly solve in a magazine 

 article or an after-dinner speech. What Vv^e want is not general 

 theories, but particular facts. We want to be shown in the laboratory 

 or in the field how far and in what way changes of function, and so 

 forth, do occur ; how the changes affect, and to what extent they affect 

 other parts of the organism ; and, above all, how far and in what way 

 these changes are inherited by the offspring of the animals or plants 

 in question. It is the fashion to abuse Professor Weismann's views 

 as theoretical and divorced from experiment and observation, but that 

 is only a fashion of the ignorant. If his conclusions come to nothing, 

 there will be left behind a large and valuable body of contributions 

 to anatomy, embryology, and natural history. Without this side of 

 his work, it is certain that the theory known as Weismannism 

 would have received neither the vast body of praise nor of abuse that 

 have been its meed. 



The Normal Nature of Ammonite Abnormalities. 



If Weismannism has done nothing else, it has served to instil 

 fresh life into the study of abnormalities and variations of all kinds. 

 This study is beset with many difficulties, and not the least of them 

 is the absence of a standard of comparison. In the investigation of 

 normal forms the observations of one investigator can be confirmed 

 and corrected by those of others. In the case of abnormalities there 

 is much more room for the error arising from personal equation, but 

 where independent investigationslead authors to similar conclusions, 

 it speaks well for the results. Curiously enough, this is to a certain 

 extent the case in reference to a paper which appeared in our last 

 number, " Can the Sexes in Ammonites be Distinguished ? ", by 

 Messrs. Buckman and Bather (p. 427). After that had gone to press 

 a paper " Ueber Ammonoiden mit 'anormaler' Wohnkammer, " was 

 received from Dr. J. F. Pompeckj.' It deals with Ammonites which 

 are said to show " abnormal body-chambers," that is to say, body- 

 chambers which in breadth or thickness are less than they should be 

 if the previous rate of increase of the shell had been maintained. 



1 Jahreshefte Vereins Naturkunde Wiirtt. 1894. Pp- 220-290, pi. iv. 



B 2 



