June 9, 1911] 



SCIENCE 



899 



0. hiennis and 0. muricata, however, the only 

 exception seems to be in the size and form of 

 the petals. 



The very interesting discovery was made by 

 J. M. Geerts* that approximately half the 

 ovules and half the pollen grains of the allo- 

 gametic species of (Enoihera are abortive. It 

 is suggested that in case of (Enoihera hiennis 

 only those ovules that carry the conica form 

 develop, those that should carry the hiennis 

 form aborting. On the other hand only those 

 pollen grains which carry the hiennis form 

 mature, those that should carry the conica 

 form failing to develop. 



"Walter T. Swingle 



v studies in arteriosclerosis 

 Much has appeared in the literature in 

 recent years upon the etiology and process of 

 development of arteriosclerosis. Many ob- 

 servations have been made upon the human 

 subject and also in experimental animals, of 

 points co-relating certain factors with the pro- 

 duction of disease in the arterial tree. In 

 most instances these factors have been care- 

 fully studied by competent observers and in 

 many instances the results have been verified 

 by others. 



The gathering of facts concerning arterio- 

 sclerosis is quite simple — the interpretation 

 of these involves much difiiculty. In carrying 

 out any experiment or in oilering reasons for 

 a given result, we are constantly reminded of 

 the manifold factors which enter a given ex- 

 periment or which are naturally present. 

 Often our experiment on animals only induces 

 altered conditions which indirectly bring 

 about the result we are seeking. That the 

 greatest care must be exercised in drawing 

 inferences from animal experimentation is 

 well illustrated in studies upon arteriosclerosis. 

 Eecently Levin and Larkin' have published 

 the results of their experiments on dogs, in 



* Geerts, J. M., ' ' Beitrage zur Cytologie und der 

 partiellen Sterilibat von (Enothera Lamarhiana," 

 in Eecueil des travaux iotaniques neerlandais, 5: 

 93-208, pi. 5-22 (N. 2-4, June, 1909), also pub- 

 lished as a separate article. 



' Jour. Exper. Med., 1911, XIII., p. 24. 



which by producing an arterio-venous anasto- 

 mosis between the external jugular vein and 

 the external carotid artery, they arrive at the 

 sweeping conclusion that " arteriosclerosis can 

 not be artificially induced in a previously 

 healthy blood-vessel by a change in the blood 

 pressure alone." To this type of conclusion 

 we must take exception. 



Levin and Larkin, experimeliting on ten 

 dogs, joined the external carotid artery to the 

 external jugular vein. In two of these dogs 

 thrombosis occurred close to the line of suture 

 in the vessels. All but two of the remaining 

 eight animals received injections of adrenalin 

 at varying periods. These eight dogs, which 

 form the positive results and from which the 

 above positive statement respecting arterio- 

 sclerosis was made, were allowed to live 102, 

 38, 72, 15, 124 and 58 and 44 days, respectively. 



No one, who has studied diverse patholog- 

 ical lesions, will deny that the distribution of 

 various lesions in organs is not uniform in 

 the animal world. Man is particularly sub- 

 ject to lesions of the circulatory system — a 

 condition not so frequent in lower animals. 

 Eabbits and horses occasionally suffer from 

 arterial lesions — more often seen in the older 

 animals and in certain breeds. Dogs and cats 

 rarely develop lesions in the arteries, even 

 under the most trying circumstances. 



This varying susceptibility still awaits an 

 explanation, but in the face of our ignorance 

 in the matter, we must assume the greatest 

 care in drawing broad conclusions or in pro- 

 posing far reaching principles. Negative ex- 

 perimental results for the dog have no positive 

 bearing upon experimental facts observed in 

 other animals. 



Much criticism is offered against the use of 

 the rabbit for experiments upon the circula- 

 tory system. The comment has been that 

 spontaneous arterial disease occurs in this 

 animal. And yet none of the critics offer any 

 suggestion for the cause of this spontaneous 

 lesion ! Properly selected animals and con- 

 trolled experiments can reduce the error of 

 " spontaneous " disease to almost a vanishing 

 point. The very feature, in the rabbit, of 

 readily reacting in its arterial tree to different 



