149 



as lIkd result of special adaptation. In refereuco to the effect of rapid 

 changes of temperature, the author finds that such alternations, how- 

 ever great and rapid they may be, do not exercise any injurious effect 

 upon the vitality of plants as long as they remain below the maximum 

 allov.'able and above the freezing point; but that such changes do exer- 

 !;iso a direct eflect upon the movement of the protoplasm, by causing 

 its cessation, even in cases where the heating or cooling 'slowly, to the 

 same degree, would not produce a similar effect. Inquiries into the 

 influence of temperature upon the rapidity of germination confirm the 

 results already obtained by ]\[r. Sachs — that for each species there is 

 a most favorable degree of temperature for growth, since grovrth takes 

 place at that point more rapidly than at any other temperature; and 

 that below this point the length of a growing radicle increases in pro- 

 portion as the temperature is elevated, while above that it isdimijiished 

 more and more as the temperature ascends. 



Inoculation foii einderpest. — In an article upon inoculation for 

 rinderpest, detailing the result of several experiments instituted in 

 Kussia on this subject, the following couclusioils are arrived at: 1. 

 Einderpest must l)e considered as a typhus of a peculiar character, which, 

 while having some resemblance to the epidemical typhus in man, differs 

 from it in its permanent course, and the persistent occurrence of a 

 catxirrhal condition in general, and ii mucous coating of the intestines 

 in particular. 2. The rinderpest is disseminated principally from the 

 steppes of As^ and other jn'ovinces of Russia. The region, however, 

 where it first arose and the causes of its origin are unknown. 3. The 

 contagion of rinderpest is transmitted, in part, by- direct contact with 

 diseased' animals, and partly by the emanations from living and dead 

 animals, affected, although not to any great distance at any one time. 

 i. In the south of Russia rinderr,ost is, comparatively, less contagious 

 and dangerous than in other portions of the empire. 5. In summer 

 and winter the rinderpest is generally less violent than in spring and 

 autumn. Autumn is the most unfavorable time for inoculation of rin- 

 derpest, the most favorable time being that in which a moderate tem- 

 l)eraturo predominates. C. All races of cattle are not equally seysitiv'e 

 to contagion of rinderpest. Those less liable are the Kirgus and Kal- 

 muck races, belonging to the stepi'ies. 7. The alleged mitigation and 

 weakening of the virus by repeated inoeulatiou, and in the succeeding 

 generations, does not prove to be substantially true, according to the 

 experiments of Robichew, as even in the fifteenth generation it did not 

 seem to have lost its activitj'. Professor Jesseu considers, however, 

 that the question of the weakening of the virus cannot be regarded as 

 closed until a special series of experiments has been instituted, in which 

 the contagion has been inoculated from the first generation, on gTadu- 

 ally, to complete inactivity. 8. It has not been determined, positively, 

 by the experiments how long the pest contagion ujaintains its aggres- 

 sive activity. In many cases the virus loses its infecting power after 

 the course of a few days ; in others it remains many months. It must, 

 nevertheless, not be overlooked that the aggressive power of the con- 

 tagion may be dependent upon its. preservation or other influences. 

 Single cases of inactivity of the virus may be explained under the sup- 

 position that this has lost its activity in consequence of the milder na- 

 ture of the epizootic, or the animals inoculated with the virus did not 

 become ill, or only in a slight degree, on account of their want of sensi- 

 tiveness to the contagion, or because they had already experienced 

 the natural disease. In regard to the action of fresh and old virus, ex- 

 periments have showji that the former generally produces more, and the 



